Weak and cowardly person (4)
I believe the answer is:
wimp
'weak and cowardly person' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for wimp that I've seen before include "Someone ineffectual" , "Drip" , "Feeble or ineffectual person" , "Namby-pamby" , "Informally, an ineffectual man" .)