As hinted at in my heading, the last couple here were a mite tricky, I thought. The rest? Well, very Mondayish, indeed. Plusjeremy will be looking at a mohnesque time, I reckon, if he knows his pub food, his cupettes and his Shakespeare. 17 plus change for this moderately erudite non-computer type.
Afore ye go! Ite missa est! and all that caper...
1 My clue cooked up for Aristotle’s school (6)
LYCEUM - anagram* of MY CLUE; pretty straightforward for those who followed the arts, but maybe a head-scratcher for IT types
5 Small cup offered by girl in sanctimonious family (8)
PANNIKIN - ANN in PI KIN; pretty much a head-scratcher for everyone, I would have thought
9 Book written in African state, primarily on Shakespearean steward (8)
MALVOLIO - VOL in MALI O (first letter of ON); I once played Antonio in Twelfth Night. I couldn't manage one of my five lines, which was 'Put up your sword!' I could only say it as if I was doing a Monty Python parody. It was so bad that I was nearly dropped from the play. And this just a year or so after wowing audiences in Zigger Zagger, where admittedly I didn't really have to act.
10 Reindeer in peril, about to be substituted for good (6)
DANCER - DANGER with the G (good) replaced by C (about, AKA circa); I rather like the surface of this clue. The other day I looked up all the various Clausian reindeer (core and peripheral) but have since forgotten all bar Vixen. Not sure what that says about me apart from the fact I am losing my, um, what do you call it...
11 Attractive grassy areas used in first half of game (8)
PLEASING - LEAS in PING [pong]; the sort of surface a setter comes up with when he's been on the sherry
12 Exercise gets first of bulky blokes losing eight stone (6)
PEBBLE - PE and initial letters of B[ulky] B[lokes] L[osing ] E[ight]
13 At home this person’s invested in fast pain relief (8)
LINIMENT - IN IM in LENT; thank goodness the setter was so precise with his/her cluing, prompting me to change my initial A to an I. I also thought of 'lineament', but fortunately that didn't fit
15 Monster involved in rather gory comeback (4)
OGRE - reverse hidden in rathER GOry
17 A type lacking finish is similar (4)
AKIN - A KIN[d]
19 Article by Catholic dignitary about an Anglo-Saxon responsibility (8)
THANEDOM - AN (an) in THE (article) DOM (Catholic dignitary); took me while to sort this out, not helped by the DOM (not being of a monkish disposition), but instead being helped by Macbeth, who was the thane of somewhere
20 Bovine bloke protecting posh legislator (6)
LUMPEN - U MP in LEN (our first random bloke); for those of you who are wondering, Karl Marx's Lumpenproletariat (magnificent word) and this lumpen have some kind of association, with the German LUMPEN (rag) influencing the German LUMP (vagabond) that is the root (apparently) of this English word
21 Old man with money picked up something to suck (8)
LOLLIPOP - POP follows sounds like 'lolly' (a slang term for money that almost no one with half a brain uses; quite popular in Australia, I am told))
22 Girl presented by one’s second son (6)
ISABEL - IS ABEL (Abel was the second son of Adam and Eve, the first being Cain and the third - and ancestor of Jesus in the Biblical account - being Seth)
23 Sustenance teachers finally sought, eating nothing in Paris (8)
NUTRIENT - RIEN (French for 'nothing') in NUT (National Union of Teachers) [sough]T; if music be the food of love, I'll have a quarter pounder and fries
24 He reigns ineptly, though fairly committed to environment (8)
GREENISH - HE REIGNS*
25 Laid back about English knight’s disclaimer (6)
DENIAL - E N in reversal of LAID
2 Peer that goes without golf throughout a number of months (8)
YEARLONG - EARL in YON (if the setter had moved on from the sherry to the Warninks Advocaat, he might describe the act of EARL going inside YON as 'Peer, that goes without') G; if some setters are born great, some achieve greatness, and others have greatness thrust upon them, then I'm not quite sure where this one fits in. (cheeky emoji winky thingie)
3 Printing unit, sound and arousing jealousy (8)
ENVIABLE - EN (printing unit) VIABLE (sound)
4 Ordinal produced by philosopher in hot resort (9)
MILLIONTH - MILL (as in John Stuart) IN HOT*
5 Food for people with shares? (10,5)
PLOUGHMANS LUNCH - cryptic definition eliciting groans that thunder from those who got it and sighs of fire from those who didn't; a Ploughman's lunch consists of half a stale baguette, a lump of cheddar, tired looking lettuce and a spoonful from a jar of inferior pickle. Great British pub fare, in other words.
6 Most elegant farm animal is French (7)
NEATEST - NEAT (bovine creature) EST ('is' in French, n'est ce pas?)
7 Sweetener giving defensive player stimulation at first (8)
KICKBACK - KICK (stimulation) BACK (as in football, not rugby - unless you're playing Bob Hiller at full-back)
8 Old Scandinavian identifies chap from the south (8)
NORSEMAN - reversal of NAMES RON (our second random bloke)
14 Greet journalist protecting usual extremists? That’s knotty (9)
NODULATED - U[sua]L (initial and final letters of the word, AKA 'extremists') in NOD AT (greet) ED (our generic hack); almost too hard a knot for me t'untie
15 Unacceptable mendacity? Not near the centre (8)
OUTLYING - OUT (unacceptable) LYING (mendacity)
16 Aussie native taking tea with male fellow lodger (4-4)
ROOM-MATE - ROO (our prototypical Aussie native - slightly more intelligent than 'Bruce') M (male) MATE (actually, maté - the tea-like milky drink favoured by some - I suppose)
17 Scope revealed by Oscar, standing in in goal (8)
AMBITION - AMBIT (scope) O in IN; okay, he's now moved onto the brandy and has slid under the tree, wearing his new socks on his hands and asking for the Mariah Carey 'All I want for Christmas is you' to be played again. If you were asked to think of the most bizarre way to express the idea of the letter O going in the word IN, you would doubtless say, 'Oh, yeah, "Oscar, standing in in".'
18 Popular mason disturbed about current sleep disorder (8)
INSOMNIA - IN MASON* around I (electrical current)
19 Money divided by male soldiers in that place (7)
THEREIN - HE (male) RE (soldiers) in TIN (another slang term for money that no one uses)
Those that are fools, let them use their talents. Well, I have used mine as best I can.
A very merry Christmas to one and all!