Lists both small and large insects (6)
I believe the answer is:
slants
'lists' is the definition.
(I've seen this in another clue)
'both small and large insects' is the wordplay.
'both small' becomes 's' (abbreviation - e.g. clothes size. I am not sure about the 'both' bit.).
'and' is a charade indicator (letters next to each other).
'large' becomes 'L' (eg in clothes sizes).
'insects' becomes 'ants' (ant is a kind of insect).
's'+'l'+'ants'='SLANTS'
Can you help me to learn more?
(Other definitions for slants that I've seen before include "Slopes, leans" , "Angles" , "chances" .)