blast vs open fire

blast is a noun but open fire is not a noun.

Word	Noun	Adjective	Verb	Adverb
blast	Yes	No	Yes	No
open fire	No	No	Yes	No

As verbs, open fire is a hyponym of blast; that is, open fire is a word with a more specific, narrower meaning than blast:

Other hyponyms of blast include blaze, blaze away, overshoot, sharpshoot, snipe, fire, gun, pump.

blast (noun)	open fire (noun)
a very long fly ball
intense adverse criticism
an explosion (as of dynamite)
a sudden very loud noise
a highly pleasurable or exciting experience
a strong current of air

blast (verb)	open fire (verb)
shatter as if by explosion	start firing a weapon
shrivel or wither or mature imperfectly
criticize harshly or violently
use explosives on
fire a shot; release
hit with great force
create by using explosives
make with or as if with an explosion
apply a draft or strong wind to to
make a strident sound