masochistic; self-tormenting; self-deprecating
Describes a person, attitude, or behavior that finds pleasure or satisfaction in one's own suffering, humiliation, or self-criticism. Often used in psychological or colloquial contexts.
He has a masochistic personality and always ends up blaming himself.
That joke was too self-deprecating and made everyone uncomfortable.
Formed from 被虐 (ひぎゃく, 'suffering inflicted by others') + 的 (てき, '-like'). The exact historical derivation is uncertain, but the word is a modern coinage based on kanji compounds.