Ignore roundabout and motorway intersection (4)
I believe the answer is:
omit
'ignore' is the definition.
(I've seen this in another clue)
'roundabout and motorway intersection' is the wordplay.
'roundabout' becomes 'O' (resembles a roundabout).
'and' means one lot of letters go next to another.
'motorway' becomes 'MI' (resembles M1, English motorway).
'intersection' becomes 'T' (T junction).
'o'+'mi'+'t'='OMIT'
(Other definitions for omit that I've seen before include "Disregard" , "Leave out or fail to do" , "Leave something out" , "Leave out or forget" , "Exclude; veto" .)