The climbing plant, as one guessed, did cover it (4)
I believe the answer is:
vine
'the climbing plant' is the definition.
(I've seen this in another clue)
'as one guessed did cover it' is the wordplay.
I cannot quite see how this works, but
'as' could be 'in' (I've seen this in other clues) and 'in' is found in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
A single letter 'v' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for vine that I've seen before include "On which grapes grow" , "Climbing, twining plant" , "Climbing plant that needs support" , "Climbing fruiting plant" , "Climber - creeper" .)