Following a female, they're regularly seen (5)
I believe the answer is:
after
'following' is the definition.
(following can mean after or as a result of)
'a female they're regularly seen' is the wordplay.
'female' becomes 'f' (abbreviation).
'regularly seen' means one should take alternating letters.
The alternating letters of 'theyre' are 'ter'.
'a'+'f'+'ter'='AFTER'
(Other definitions for after that I've seen before include "back along > deck" , "since" , "Following - behind" , "Pursuing" , "At a later time or behind" .)