Fly like some insects, or bat (7)
I believe the answer is:
flutter
'bat' is the definition.
(synonyms)
'fly like some insects' is the wordplay.
'some' suggests taking the first letters.
'insects' becomes 'utter' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letters of 'fly like' is 'fl'.
'fl'+'utter'='FLUTTER'
'or' acts as a link.
Can you help me to learn more?
(Other definitions for flutter that I've seen before include "Fly unsteadily; small bet" , "Informally a slight gamble as on a horse" , "Small bet; beat feebly" , "Move one's eyelashes - move like a butterfly - bet" , "Bat" .)