Thus see a moderate ...
I believe the answer is:
ease off
'moderate' is the definition.
(I've seen this before)
'thus see a' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
an anagram of 'see' is 'ese' which is within the left over letters.
The remaining letters 'off' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ease off that I've seen before include "relieve tension" , "reduce tension" , "Throttle back" , "relent" , "Slacken gradually" .)