Toy top’s initial whirling motion to endure (5,4)
I believe the answer is:
teddy bear
'toy' is the definition.
(teddy bear is a kind of toy)
'top's initial whirling motion to endure' is the wordplay.
'initial' suggests taking the first letters.
'whirling motion' becomes 'eddy' (type of whirlpool).
'to endure' becomes 'bear' ('bear' can be a synonym of 'endure').
The initial letter of 'tops' is 't'.
't'+'eddy'+'bear'='TEDDY BEAR'
(Other definitions for teddy bear that I've seen before include "cling to this for comfort?" , "Cuddly ursine" , "Rupert, perhaps" , "what kid may be allowed at bedtime" , "Soft toy" .)