Cross Rhode Island with a sort of light (5)
I believe the answer is:
riled
'cross' is the definition.
(I've seen this before)
'rhode island with a sort of light' is the wordplay.
'rhode island' becomes 'RI' (US postal abbreviation).
'with' means one lot of letters go next to another.
'a sort of light' becomes 'led' (light emitting diode).
'ri'+'led'='RILED'
(Other definitions for riled that I've seen before include "Cross" , "Vexed" , "Nettled" , "Irritated, provoked" , "Annoyed" .)