The Speaker’s looked briefly annoyed (6)
I believe the answer is:
piqued
'annoyed' is the definition.
(piqued means annoyed or irritated)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for piqued that I've seen before include "Having a feeling of hurt pride" , "Needled" , "put out" , "Felt resentment" , "Felt irritated" .)