Illusory change of gear on the motorway (6)
I believe the answer is:
mirage
'illusory change' is the definition.
The answer and definition can be both types of natural phenomena as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'of gear on the motorway' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'on' is an insertion indicator (as in clothing 'on' a person).
'the motorway' becomes 'mi' (resembles M1, English motorway).
'gear' anagrammed gives 'rage'.
'rage' placed around 'mi' is 'MIRAGE'.
Can you help me to learn more?
(Other definitions for mirage that I've seen before include "Illusion caused by atmospheric refraction" , "French fighter aircraft" , "You might see this in desert" , "Illusory sighting" , "illusory thing" .)