Liquid he canned and improved (8)
I believe the answer is:
enhanced
'improved' is the definition.
(enhancing is a kind of improving)
'liquid he canned' is the wordplay.
'liquid' indicates an anagram.
'he'+'canned'='hecanned'
'hecanned' anagrammed gives 'ENHANCED'.
'and' acts as a link.
(Other definitions for enhanced that I've seen before include "Improved (upon)" , "Improved or increased the value" , "Increased the attractiveness of, improved" , "Heightened" , "Increased in value or quality" .)