Fashionable greeting initially brought it in check (7)
I believe the answer is:
inhibit
'check' is the definition.
(inhibiting is a kind of checking)
'fashionable greeting initially brought it' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'greeting' becomes 'hi' (hi is a kind of greeting).
'initially' says to take the initial letters.
The initial letter of 'brought' is 'b'.
'in'+'hi'+'b'+'it'='INHIBIT'
'in' acts as a link.
(Other definitions for inhibit that I've seen before include "Check - prevent" , "Limit the range or extent of" , "Prevent expression of" , "Hold back" , "Curb" .)