opine vs speak up

opine and speak up both are verbs.

Word	Noun	Adjective	Verb	Adverb
opine	No	No	Yes	No
speak up	No	No	Yes	No

As verbs, opine and speak up are synonyms defined as:

opine and speak up: express one's opinion openly and without fear or hesitation

Other synonyms of opine include animadvert, sound off, speak out.

opine (verb)	speak up (verb)
expect, believe, or suppose	express one's opinion openly and without fear or hesitation
express one's opinion openly and without fear or hesitation	speak louder; raise one's voice