Where does “کٹھن” come from?

کٹھن (Urdu) comes from Sanskrit कठिन, from Sanskrit कठ् — to live in distress.

کٹھن (Urdu): difficult; hard; arduous

Definitions

Step	Language	Word	Meaning
1	Sanskrit	कठिन	difficult; stiff, hard, firm; harsh, cruel,...
2	Sanskrit	कठ्	to live in distress

کٹھن — Etymology, Origin & Word History | Etymology Explorer