Model child-minder (6)

I believe the answer is:

sitter

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

'model' is the definition.
(I know that model can be written as sitter)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for sitter that I've seen before include "Sedentary baby minder?" , "Baby minder for pay" , "Person posing for a portrait" , "Extremely easy task" , "easy target" .)

I've seen this clue in The Globe and Mail.

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