Row involving disheartened tinker (4)
I believe the answer is:
tier
'row' is the definition.
(a tier is a row of things)
'disheartened tinker' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters).
'tinker' with its middle removed is 'TIER'.
'involving' acts as a link.
(Other definitions for tier that I've seen before include "Person joining" , "Wedding cake layer" , "Row, layer" , "One making knot - level" , "Level within hierarchy" .)