Missing leader, draws lots (6)
I believe the answer is:
oodles
'lots' is the definition.
('oodles' can be a synonym of 'lots')
'missing leader draws' is the wordplay.
'missing leader' means to remove the first letter (leader meaning lead letter).
'draws' becomes 'doodles' (doodling is a kind of drawing).
'doodles' with its first letter taken away is 'OODLES'.
(Other definitions for oodles that I've seen before include "Bags" , "Large number or amount" , "Tons, scads" , "'Lashings, heaps (6)'" , "Lashings, loads" .)