Drifting target - comparatively little! (7)
I believe the answer is:
aimless
'drifting' is the definition.
('aimless' can be a synonym of 'drifting')
'target comparatively little' is the wordplay.
'target' becomes 'aim' ('aim' can be a synonym of 'target'**).
'comparatively little' becomes 'less' (I've seen this before).
'aim'+'less'='AIMLESS'
(Other definitions for aimless that I've seen before include "without sense of purpose" , "Melissa (anag) -- unmotivated" , "Lacking purpose" , "Rambling" , "Without purpose or target" .)