Inflexible person's bad luck endlessly meeting resistance (9)
I believe the answer is:
hardliner
'inflexible person's' is the definition.
'hardliner' can be an answer for 'person's' (hardliner is a kind of person). I am unsure of the 'inflexible' bit.
'bad luck endlessly meeting resistance' is the wordplay.
'bad luck' becomes 'hard lines' (phrase used to express commiserations or sympathy).
'endlessly' means to remove the last letter.
'meeting' means one lot of letters go next to another.
'resistance' becomes 'r' (electronics abbreviation).
'hardlines' with its last letter taken off is 'hardline'.
'hardline'+'r'='HARDLINER'
Can you help me to learn more?
(Other definitions for hardliner that I've seen before include "One committed to an uncompromising policy" , "Resolute advocate" , "Uncompromising advocate" , "One pursuing an uncompromising policy" , "Inflexible ideologue" .)