Servile flatterer (7)
(Other definitions for crawler that I've seen before include "Internet search program" , "Sycophant" , "Figure that's greasy" , "Slow driver" , "Obsequious person" .)
'servile flatterer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sycophant that I've seen before include "old informer" , "receiving ultimate in flattery from one such?" , "Servile flatterer" , "Uriah Heep, say" , "obsequious one" .)