Attention given by nobleman, briefly (3)
I believe the answer is:
ear
'attention' is the definition.
(ear is a kind of attention)
'nobleman briefly' is the wordplay.
'nobleman' becomes 'earl' (earl is a kind of nobleman).
'briefly' means to remove the last letter.
'earl' with its final letter removed is 'EAR'.
'given by' is the link.
(Other definitions for ear that I've seen before include "Bit of corn" , "Hearing aid?" , "Attention; an organ" , "'Give every man thine ..., but few thy voice' (Hamlet)" , "Hammer in this" .)