Some avoid lectures, spend time doing nothing (4)
I believe the answer is:
idle
'doing nothing' is the definition.
(I've seen this before)
'some avoid lectures spend' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'IDLE' is hidden within 'avoid lectures spend'.
'time' is the link.
(Other definitions for idle that I've seen before include "Loaf" , "Ineffectual" , "Not in action or at work" , "Not busy" , "Eric, perhaps" .)