Nobel is knighted with a dagger (7)
I believe the answer is:
obelisk
'a dagger' is the definition.
(synonyms)
'nobel is knighted with' is the wordplay.
'with' says the answer is hidden in the clue.
'OBELISK' is hidden within 'nobel is knighted'.
(Other definitions for obelisk that I've seen before include "Needle-like column" , "Tapering monumental pillar" , "Tapering, rectangular stone column" , "Tapering square pillar" , "Square stone column that tapers" .)