set off vs roar off

set off and roar off both are verbs.

Word	Noun	Adjective	Verb	Adverb
set off	No	No	Yes	No
roar off	No	No	Yes	No

As verbs, roar off is a hyponym of set off; that is, roar off is a word with a more specific, narrower meaning than set off:

Other hyponyms of set off include lift off, take off, blaze, blaze out, sally forth, sally out.

set off (verb)	roar off (verb)
cause to burst with a violent release of energy	leave at high speed making a loud sound
set in motion or cause to begin
direct attention to, as if by means of contrast
provoke or stir up
put in motion or move to act
depart for someplace
make up for