Gather before noon on a ship (5)
I believe the answer is:
amass
'gather' is the definition.
('amass' can be a synonym of 'gather')
'before noon on a ship' is the wordplay.
'before noon' becomes 'am'.
'on' is a charade indicator (letters next to each other).
'ship' becomes 'ss'.
'am'+'a'+'ss'='AMASS'
(Other definitions for amass that I've seen before include "Accumulate over time" , "run up?" , "Sodium chloride" , "Accumulate, pile up" , "Collect, hoard" .)