infernal machine vs time bomb

infernal machine and time bomb both are nouns.

Word	Noun	Adjective	Verb	Adverb
infernal machine	Yes	No	No	No
time bomb	Yes	No	No	No

As nouns, infernal machine and time bomb are synonyms defined as:

infernal machine and time bomb: a bomb that has a detonating mechanism that can be set to go off at a particular time

infernal machine (noun)	time bomb (noun)
a bomb that has a detonating mechanism that can be set to go off at a particular time	a bomb that has a detonating mechanism that can be set to go off at a particular time
	a problematic situation that will eventually become dangerous if not addressed