Living at host's expense is standard when current credit cut (9)
I believe the answer is:
parasitic
'living at host's expense' is the definition.
I can't tell whether this defines the answer.
'standard when current credit cut' is the wordplay.
'standard' becomes 'par' (standard of play in golf).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'current' becomes 'I' (physics symbol).
'credit cut' becomes 'tic' (I've seen this in other clues).
'par'+'as'+'i'+'tic'='PARASITIC'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for parasitic that I've seen before include "Living on another like flea" , "Living at another creature's expense" , "Sponging" , "Living off another organism" , "hanging on?" .)