Disclose European vehicle at first has nothing revolutionary (6)
I believe the answer is:
evolve
'disclose' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how one could define the other.
'european vehicle at first has nothing revolutionary' is the wordplay.
'at first' suggests taking the first letters.
'has' says to put letters next to each other.
'nothing' becomes 'love' (love is zero in tennis).
'revolutionary' says the letters should be written backwards (letters revolve around).
The first letters of 'european vehicle' is 'ev'.
'ev'+'love'='evlove'
'evlove' reversed gives 'EVOLVE'.
Can you help me to learn more?
(Other definitions for evolve that I've seen before include "Unfold" , "Develop or change very gradually (6)" , "Develop slowly" , "Gradually acquire new characteristics" , "Develop by natural selection" .)