US agent collaring swimmer became irritated (6)
I believe the answer is:
frayed
'irritated' is the definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?
'us agent collaring swimmer' is the wordplay.
'us agent' becomes 'fed' (short for a federal agent).
'collaring' means one lot of letters goes inside another.
'swimmer' becomes 'ray' (ray is a type of fish).
'fed' going around 'ray' is 'FRAYED'.
'became' is the link.
Can you help me to learn more?
(Other definitions for frayed that I've seen before include "Of garment, worn and with loose threads" , "Well worn with loose threads" , "Torn at the edges as from wear" , "Worn at the edge" , "Ragged at the edges" .)