Regularly observed twitch (3)

I believe the answer is:

tic

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

'regularly observed twitch' is the definition.
'tic' can be an answer for 'twitch' (tic is a kind of twitch). I'm not sure about the 'regularly observed' bit.

'regularly observed twitch' is the wordplay.
'regularly observed' means one should take alternating letters (letters selected at regular intervals).
The alternating letters of 'twitch' are 'TIC'.

Can you help me to learn more?

(Other definitions for tic that I've seen before include "Regular muscular twitch" , "Involuntary muscular spasm" , "Convulsive spasm" , "Convulsion" , "Facial muscle spasm" .)

I've seen this clue in The Times.

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.