Reasonable to get large gift (5)
I believe the answer is:
flair
'gift' is the definition.
(flair is a kind of gift)
'reasonable to get large' is the wordplay.
'reasonable' becomes 'fair' ('fair' can be a synonym of 'reasonable'**).
'to get' means one lot of letters goes inside another.
'large' becomes 'l'.
'fair' going around 'l' is 'FLAIR'.
(Other definitions for flair that I've seen before include "Stylishness; talent" , "Elan; panache" , "Style, panache" , "Taste" , "Natural ability or elegance" .)