Fawn caught by crude line (5)
I believe the answer is:
crawl
'fawn' is the definition.
('crawl' can be a synonym of 'fawn')
'caught by crude line' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'by' means one lot of letters go next to another.
'crude' becomes 'raw' ('raw' can be a synonym of 'crude').
'line' becomes 'l'.
'c'+'raw'+'l'='CRAWL'
(Other definitions for crawl that I've seen before include "be overrun" , "Make no haste" , "inch" , "Proceed on hands and knees" , "Suck up to" .)