Cups for gullible people (4)
I believe the answer is:
mugs
'gullible people' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for mugs that I've seen before include "Drinking cups" , "'Cups, faces and fall guys (4)'" , "Attacks" , "Faces (sl.)" , "Cylindrical cups without saucer" .)