Sloth perplexed last of zoologists in Leeds (8)
I believe the answer is:
idleness
'sloth' is the definition.
(I've seen this before)
'perplexed last of zoologists in leeds' is the wordplay.
'perplexed' is an anagram indicator.
'last of' suggests the final letters.
The last letter of 'zoologists' is 's'.
's'+'in'+'leeds'='sinleeds'
'sinleeds' is an anagram of 'IDLENESS'.
(Other definitions for idleness that I've seen before include "State of inactivity" , "unemployment" , "Inaction" , "Sloth - there may be love in it" , "Send lies (anag.)" .)