Become tall and seedy (4)

I believe the answer is:

bolt

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

'become' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for bolt that I've seen before include "Flash of lightening - run away" , "eat food quickly and > lock up" , "Crossbow missile" , "Fastening pin; run away" , "Involved in security" .)

I've seen this clue in the Evening Standard.

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.