Beginning to climb in French south, sweep across sky (4)
I believe the answer is:
scud
'sweep across sky' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'beginning to climb in french south' is the wordplay.
'beginning to' indicates taking the first letters.
'in' is an insertion indicator.
'french south' becomes 'sud' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letter of 'climb' is 'c'.
'c' inserted inside 'sud' is 'SCUD'.
Can you help me to learn more?
(Other definitions for scud that I've seen before include "(Of clouds) move quickly" , "At sea - run before a gale" , "Skim along; Russian missile" , "Move quickly (as if running before a gale)" , "Missile - move swiftly and smoothly" .)