Mister Solo shot after a little hesitation (7)
I believe the answer is:
'mister' is the definition.
(aerosol sprays release a mist of liquid)
'solo shot after a little hesitation' is the wordplay.
'shot' is an anagram indicator.
'after' says to put letters next to each other.
'little hesitation' becomes 'er' (expression of hesitation).
'solo' with letters rearranged gives 'osol'.
'osol' put after 'aer' is 'AEROSOL'.
(Other definitions for aerosol that I've seen before include "Air spray" , "Pressurised canister that emits spray of fine droplets" , "Substance sealed in container and released as fine spray" , "Liquid in a container under pressure" , "Spray creator" .)