Affectionate women are mostly married (4)
I believe the answer is:
warm
'affectionate' is the definition.
(synonyms)
'women are mostly married' is the wordplay.
'women' becomes 'w' (standard abbreviation).
'mostly' means to remove the last letter.
'married' becomes 'm'.
'are' with its last letter removed is 'ar'.
'w'+'ar'+'m'='WARM'
(Other definitions for warm that I've seen before include "On the brink of making discovery" , "not cool?" , "Animated" , "easily aroused" , "showing enthusiasm" .)