Gun with small nose (7)
I believe the answer is:
shooter
'gun' is the definition.
(I've seen this before)
'with small nose' is the wordplay.
'with' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'nose' becomes 'hooter' (hooter can informally mean someone's nose).
's' put next to 'hooter' is 'SHOOTER'.
(Other definitions for shooter that I've seen before include "photographer?" , "that rolls along the ground" , "Hit man" , "aiming to score goal?" , "Gun user" .)