Perform extemporaneously, express displeasure and walk (5-4)

I believe the answer is:

sight-read

I'm a little stuck... Click here to teach me more about this clue!

'perform' is the definition.
(sight-reading is a kind of performing)

'extemporaneously express displeasure and walk' is the wordplay.
'extemporaneously express displeasure' becomes 'sigh' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' means one lot of letters go next to another.
'walk' becomes 'tread' (treading is a kind of walking).
'sigh'+'tread'='SIGHT-READ'

Can you help me to learn more?

(Another definition for sight-read that I've seen is " Interpret music without preparation".)

I've seen this clue in The Hindu.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.