Men lost on manoeuvres inclined to retire? (9)
I believe the answer is:
somnolent
'inclined to retire?' is the definition.
(causing sleepiness)
'men lost on manoeuvres' is the wordplay.
'manoeuvres' indicates an anagram (letters manoeuvred in a new way).
'men'+'lost'+'on'='menloston'
'menloston' anagrammed gives 'SOMNOLENT'.
(Other definitions for somnolent that I've seen before include "drifting off" , "Drowsy - lost on men (anag)" , "Dozy" , "Sleepy, drowsy" , "Comatose" .)