Marriageable (6)
I believe the answer is:
nubile
'marriageable' is the definition.
(I know that marriageable can be written as nubile)
This is the entire clue.
(Other definitions for nubile that I've seen before include "Of marriageable age?" , "Young and sexy" , "Sexually mature" , "Marriageable, physically attractive" , "Of girls or women who are eligible to marry" .)