godan ~る verb / intransitive verb:

• to rot; to go bad; to decay; to spoil; to fester; to decompose; to turn sour (e.g. milk)
• to corrode; to weather; to crumble
• to become useless; to blunt; to weaken (from lack of practice)
• to become depraved; to be degenerate; to be morally bankrupt; to be corrupt
• to be depressed; to be dispirited; to feel discouraged; to feel down ➜ 気が腐る【きがくさる】

auxiliary verb / godan ~る verb:

• to have the audacity to; to be bastard enough to - after the -masu stem of a verb; indicates scorn or disdain for another's action - usually written using kana alone - Kansai dialect ➜ やがる

godan ~る verb / intransitive verb:

• to lose a bet - archaism
• to be drenched; to become sopping wet - archaism