sub vs sonar

sub and sonar both are nouns.

Word	Noun	Adjective	Verb	Adverb
sub	Yes	No	Yes	No
sonar	Yes	No	No	No

sub (noun)	sonar (noun)
a submersible warship usually armed with torpedoes	a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return
a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States

sub (verb)	sonar (verb)
be a substitute