ACROSS
 1. S QUIRE ARCH = SQUIREARCH <gentleman>
 6. <stinker> ATOC = (.t)ATO C(h.)
 9. CHO_ LENT = CHOLENT <food on Saturday>
10. <displaying old form> ATAVISM = VISA* inside ATM
12. <ring> TINTINNABULATE = TINTIN NAB U LATE
14. <bony> MALLEOLAR = MOLAR outside ALL _E
16. <clip> IDENT = ID EST, S→N
17. ←OR UFO← = OFURO <tub>
19. ←(.e)AR A PILL UN(d.)← = NULLIPARA <childless adult>
21. HYPE ←SEAR← THE TIC = HYPERAESTHETIC <oversensitive>
24. O ←LEMON E← = OENOMEL <drink>
25. ROO IN _EK_ = ROOINEK <Brit>
26. _E_ MMA = EMMA <coded letter>
27. <killjoy> SOBERSIDES = SO BESIDES outside R

DOWN
 1. SIC _E = SICE <die roll>
 2. _UXO_ _RI_ _AL_ = UXORIAL <wifely>
 3. <X-ray> ROENTGENOGRAM = ROE GENT* + NOG + RAM
 4. A C ←NIT← = ACTIN <protein for muscles>
 5. CHAP ARR + A L = CHAPARRAL <shrubland>
 7. TRIBE outside AD = TRIBADE <lesbian>
 8. (SCRAP METAL)* = CAMPESTRAL <in the countryside>
11. A LUMINOUS outside FIRE* = ALUMINIFEROUS <like emeralds?>
13. <gun> SMOOTHBORE = →"BOOTH S'MORE"←
15. <card game> LANTERLOO = _L ANTE R LOO
18. <language schools> ULPANIM = PAN I inside ULM
20. <gave away> ALIENED = A LIE N_ ED
22. ←EG RAT← = TARGE <shield>
23. OK ←SA← = OKAS <Turkish weights>