Nimble girls regularly taken in by date (5)
I believe the answer is:
agile
'nimble' is the definition.
(agile can mean nimble or athletic)
'girls regularly taken in by date' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'taken in by' indicates putting letters inside.
'date' becomes 'age' (both can mean to get older).
The alternate letters of 'girls' are 'il'.
'il' going within 'age' is 'AGILE'.
(Other definitions for agile that I've seen before include "Quick-moving, supple" , "Nimble, supple" , "Mentally acute" , "Physically quick and nimble" , "Moving quickly/easily" .)