Cloud and rain -- ultimately I am taking vehicle (6)
I believe the answer is:
nimbus
'cloud' is the definition.
(nimbus is a kind of cloud)
'rain ultimately i am taking vehicle' is the wordplay.
'ultimately' says to take the final letters.
'i am' becomes 'im'.
'taking' means one lot of letters go next to another.
'vehicle' becomes 'bus' (I've seen this before).
The last letter of 'rain' is 'n'.
'n'+'im'+'bus'='NIMBUS'
'and' acts as a link.
(Other definitions for nimbus that I've seen before include "Type of rain cloud" , "Is numb (anag)" , "A black rain cloud" , "Dirty cloud; saintly light" , "Bums in (anag)" .)