Little beast's excessive hesitation (5)
I believe the answer is:
otter
'little beast's' is the definition.
'otter' can be an answer for 'beast's' (I have seen 'Aquatic beast' mean 'otter' so perhaps 'beast' could also mean 'otter'). I'm not sure about the 'little' bit.
'excessive hesitation' is the wordplay.
'excessive' becomes 'ott' (short for 'over the top' - informal British).
'hesitation' becomes 'er' (sound used when hesitating).
'ott'+'er'='OTTER'
Can you help me to learn more?
(Other definitions for otter that I've seen before include "Aquatic beast" , "Fish-eating mammal" , "furry animal" , "Aquatic river mammal" , "Carnivorous aquatic mammal" .)