Sort of conk out - no reason - crossing motorway (5,4)
I believe the answer is:
roman nose
'sort of conk' is the definition.
The definition and answer can be both body parts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'out no reason crossing motorway' is the wordplay.
'out' indicates anagramming the letters.
'crossing' indicates putting letters inside (to cross can mean to go over or around).
'motorway' becomes 'M' (as in motorway names - M1, M4 etc).
'no'+'reason'='noreason'
'noreason' is an anagram of 'roannose'.
'roannose' enclosing 'm' is 'ROMAN NOSE'.
Can you help me to learn more?
(Other definitions for roman nose that I've seen before include "feature with bridge" , "personal feature" , "prominent Italian feature" , "outstanding feature" .)