Severe shortage (6)
I believe the answer is:
dearth
'severe shortage' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dearth that I've seen before include "In short supply" , "Shortage, paucity" , "Scarcity, paucity" , "Scarcity - famine" , "Hatred (anag) -- shortage" .)