Bad
caustic - Sarcastic or severely critical, often in a hurtful or biting manner; or able to burn or corrode organic tissue, typically referring to chemicals or substances.
The caustic chemical spilled onto the floor and quickly started to eat away at the floor surface.
relent - To surrender or agree after resisting or opposing, often due to persuasion, pressure, or changing circumstances.
Out of pride, he would always refuse to accept assitance, but when things hit rock bottom, he relented, and finally accepted help from others.