They slip easily from a shelf in the ship (7)
I believe the answer is:
sledges
'they slip easily' is the definition.
The definition suggests an adverb but the answer is not.
'a shelf in the ship' is the wordplay.
'a shelf' becomes 'ledge' ('ledge' can be a synonym of 'shelf').
'in the' means one lot of letters goes inside another.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'ledge' inserted inside 'ss' is 'SLEDGES'.
'from' is the link.
Can you help me to learn more?
(Other definitions for sledges that I've seen before include "Sleighs; hammers" , "insults" , "Snow carts" , "More than one big hitter" .)