Senior members became more inquisitive (6)
I believe the answer is:
nosier
'more inquisitive' is the definition.
(I've seen this in another clue)
'senior members' is the wordplay.
'members' is an anagram indicator (members or parts of the anagram in a different way).
'senior' with letters rearranged gives 'NOSIER'.
'became' is the link.
(Other definitions for nosier that I've seen before include "More inquisitive" , "More curious in nasal way" , "rather curious" , "Senior (anag)" , "More curious, being senior" .)