Large container holding sulphur (4)
I believe the answer is:
vast
'large' is the definition.
('vast' can be similar in meaning to 'large')
'container holding sulphur' is the wordplay.
'container' becomes 'vat' (vat is a kind of container).
'holding' indicates putting letters inside.
'sulphur' becomes 's' ('S' can be a synonym of 'sulphur').
'vat' placed around 's' is 'VAST'.
(Other definitions for vast that I've seen before include "Unusually great" , "Colossal" , "Extremely large or extensive" , "Gigantic" , "Astronomical" .)