Trick to fitting log base in willowy frame (7)

I believe the answer is:

sleight

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

'trick' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for sleight that I've seen before include "Artful trick" , "Cunning action" , "It's deceiving to the eye" , "Dexterity (usually of hand)" , "Trickery" .)

I've seen this clue in the Sydney Morning Herald.

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.