One enthralled by hooter's sound (5)
I believe the answer is:
noise
'sound' is the definition.
(noise is a kind of sound)
'one enthralled by hooter's' is the wordplay.
'one' becomes 'i' (Roman numeral).
'enthralled by' is an insertion indicator ('enthral' can mean 'capture').
'hooter' becomes 'nose' (I've seen this before).
'i' going inside 'nose' is 'NOISE'.
(Other definitions for noise that I've seen before include "Virgil's birthplace" , "Kind of pollution" , "Excessive sound" , "Hum" , "Sound of any kind" .)