No out-of-the-way incursion! (6)
I believe the answer is:
inroad
'incursion' is the definition.
(I know that inroad is a type of invasion)
'no out-of-the-way' is the wordplay.
'no out of' becomes 'in' (I am not sure about this - if you are sure you should believe this answer much more).
'the way' becomes 'road' (road is a kind of way).
'in'+'road'='INROAD'
Can you help me to learn more?
(Other definitions for inroad that I've seen before include "Incursion, raid" , "Encroachment; hostile attack" , "Ordain (anag.)" , "Foray" , "Sudden attack made into a country" .)