Supply has been cut and I'm not able to see petitioner (10)
I believe the answer is:
supplicant
'petitioner' is the definition.
(I know that petitioner can be written as supplicant)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for supplicant that I've seen before include "petitioner" , "Person petitioning" , "one asks" , "beggar" , "One petitioning" .)