Shortage of tangled thread (6)
I believe the answer is:
dearth
'shortage' is the definition.
(dearth can mean a shortage or lack)
'tangled thread' is the wordplay.
'tangled' indicates an anagram.
'thread' is an anagram of 'DEARTH'.
'of' is the link.
(Other definitions for dearth that I've seen before include "Severe lack" , "Hatred (anag) -- shortage" , "Scarcity - famine" , "Red hat for scarcity" , "Acute shortage" .)