Scrap old bank holiday (4)

I believe the answer is:

whit

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

But I can't explain it at all! Could you help me understand?

(Other definitions for whit that I've seen before include "Iota" , "Very small amount" , "Very small part - Christian festival" , "smallest bit imaginable" , "Modicum" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app