Talking on and on and frightening one (8)
I believe the answer is:
rattling
'talking' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'on and on and frightening one' is the wordplay.
I cannot really understand how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for rattling that I've seen before include "Making short hard sounds" , "worrying" , "Travelling at great speed" , "indication of loose parts?" , "Chattering" .)