forthwith vs right away

forthwith and right away both are adverbs.

Word	Noun	Adjective	Verb	Adverb
forthwith	No	No	No	Yes
right away	No	No	No	Yes

As adverbs, forthwith and right away are synonyms defined as:

forthwith and right away: without delay or hesitation; with no time intervening

Other synonyms of forthwith include at once, directly, immediately, instantly, like a shot, now, straight off, straightaway.

forthwith (adverb)	right away (adverb)
without delay or hesitation; with no time intervening	without delay or hesitation; with no time intervening
	at once (usually modifies an undesirable occurrence)