Gertrude possibly isn’t bothered about termination of spouse (5)
I believe the answer is:
stein
'gertrude' is the definition.
(I've seen this in another clue)
'isn't bothered about termination of spouse' is the wordplay.
'bothered' indicates an anagram.
'about' indicates putting letters inside.
'termination of' says to take the final letters (the letter which terminates the word).
The final letter of 'spouse' is 'e'.
'isnt' anagrammed gives 'stin'.
'stin' placed around 'e' is 'STEIN'.
'possibly' acts as a link.
(Other definitions for stein that I've seen before include "Beer-mug" , "Glass" , "Gertrude __, avant-garde US author, d. 1946" , "German earthenware beer mug" , "Inset into earthenware mug for beer" .)