Woman’s clear about new tendency to gather (4,8)
I believe the answer is:
herd instinct
'tendency to gather' is the definition.
'woman's clear about new' is the wordplay.
'woman's' becomes 'her'.
'clear' becomes 'distinct' ('distinct' can be a synonym of 'clear'**).
'about' means one lot of letters goes inside another.
'new' becomes 'n'.
'distinct' placed around 'n' is 'dinstinct'.
'her'+'dinstinct'='HERD-INSTINCT'
(Other definitions for herd instinct that I've seen before include "new feeling of congregation" , "Safety-in-numbers feeling" , "Animals' natural togetherness" .)