Reporter's briefly looked annoyed (6)
I believe the answer is:
piqued
'annoyed' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for piqued that I've seen before include "Needled" , "Having a feeling of hurt pride" , "Felt resentment" , "Felt irritated" , "put out" .)