This crossword No. 15166 clues and answers were published on Sat 15 Dec 2018 and the puzzle can be visited by following The Guardian Quick Crossword No. 15166 link.
All Across Clues and Answers:
1-across – Adapt to a new environment : ACCLIMATISE
9-across – Mischievous fairy : HOBGOBLIN
10-across – Scottish mountain : BEN
11-across – Plunder : RIFLE
13-across – Mythical horse/man : CENTAUR
14-across – Noisy, lavish party : THRASH
15-across – Diverse : VARIED
18-across – Foul-smelling : NOISOME
20-across – Incantation : SPELL
21-across – Wrong : SIN
22-across – Grass : INFORMANT
24-across – Likely winner : FRONTRUNNER
All Down Clues and Answers:
2-down – Male swan : COB
3-down – Unties : LOOSENS
4-down – Ill will : MALICE
5-down – Projection used in a mortise joint : TENON
6-down – Underwater : SUBMARINE
7-down – Physiological need to drink — resists hint : THIRSTINESS
8-down – Disbelief : INCREDULITY
12-down – Alien : FOREIGNER
16-down – Contestant losing by a large margin : ALSORAN
17-down – Young cow : HEIFER
19-down – Constellation on the celestial equator — giant hunter of Greek mythology : ORION
23-down – Intoxicating drink : ALE
This crossword has in total 24 where 12 are across and 12 are down.