painful vs unspeakable

painful and unspeakable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
painful	No	Yes	No	No
unspeakable	No	Yes	No	No

As adjectives, painful and unspeakable are synonyms defined as:

Other synonyms of painful include abominable, atrocious, awful, dreadful, terrible.

painful (adjective)	unspeakable (adjective)
causing physical or psychological pain	exceptionally bad or displeasing
exceptionally bad or displeasing	defying expression or description
causing physical discomfort	too sacred to be uttered
causing misery or pain or distress