Be emphatic about the pressure (6)
I believe the answer is:
stress
'pressure' is the definition.
(I've seen this in another clue)
'be emphatic about the' is the wordplay.
I cannot really understand how this works, but
'about' could be 're' (regarding) and 're' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
The remaining letters 'sss' is a valid word 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 stress that I've seen before include "Emphasise the pressure" , "suffering" , "Tension; emphasis" , "Tension - accent" , "Dwell on" .)