Supposed to have been overbold (8)

I believe the answer is:

presumed

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

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

I don't understand the remainder of the clue.

(Other definitions for presumed that I've seen before include "Taken for granted" , "Supposed" , "thought" , "expected" , "Was impertinent" .)

I've seen this clue in the Evening Standard.

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