Slipperiness of rim (3)

I believe the answer is:

lip

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

'rim' is the definition.
(both can mean the edge of something)

'slipperiness' is the wordplay.
'LIP' is hidden within the letters.
However, I'm not sure how this is indicated.

'of' is the link.

Can you help me to learn more?

(Other definitions for lip that I've seen before include "Insolence (slang)" , "Edge, rim" , "sauciness" , "Fleshy fold of mouth tissue" , "Part of mouth or cheek" .)

I've seen this clue in The Mirror.

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.