Nose is running for ages (4)
I believe the answer is:
eons
'ages' is the definition.
(eon is a kind of age)
'nose is running' is the wordplay.
'is running' is an anagram indicator (the letters run around to different places).
'nose' anagrammed gives 'EONS'.
'for' acts as a link.
(Other definitions for eons that I've seen before include "Divisions of archaeological time" , "Vast ages" , "Times" , "Long periods of time - noes have it" , "Years and years" .)