Hands down back of settee, a number of items not quite retrieved, unknown quantity (6)
I believe the answer is:
easily
'hands down' is the definition.
(synonyms)
'back of settee a number of items not quite retrieved unknown quantity' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'number' could be 'l' (L is an example) and 'l' is found within the answer.
'unknown' could be 'y' (algebra) and 'y' is found in the answer.
'quantity' could be 's' (S is an example) and 's' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for easily that I've seen before include "With little difficulty" , "Very probably" , "Simply" , "without doubt" , "Comfortably" .)