Lethargy defeats rising, requiring injection of pressure (6)
I believe the answer is:
stupor
'lethargy' is the definition.
(I've seen this before)
'defeats rising requiring injection of pressure' is the wordplay.
I cannot really understand how this works, but
'rising' could be 'up' (similar in meaning) and 'up' is located in the answer.
'of' could be 'o' and 'o' is present in the answer.
The remaining letters 'str' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for stupor that I've seen before include "State of shock" , "Coma, lethargy" , "state of unawareness" , "numbness" , "Insensible state" .)