Involve row hiding at back (6)
I believe the answer is:
entail
'involve' is the definition.
(entail means to involve or require)
'row hiding at back' is the wordplay.
'row' becomes 'line' (as in a row of things).
'hiding' means one lot of letters goes inside another.
'back' says the letters should be written in reverse.
'line' going around 'at' is 'liatne'.
'liatne' in reverse letter order is 'ENTAIL'.
(Other definitions for entail that I've seen before include "legal restriction" , "outmoded fashion" , "Have as a logical consequence" , "Call for" , "Restriction on inheritance" .)