iceberg vs growler

iceberg and growler both are nouns.

Word	Noun	Adjective	Verb	Adverb
iceberg	Yes	No	No	No
growler	Yes	No	No	No

As nouns, growler is a hyponym of iceberg; that is, growler is a word with a more specific, narrower meaning than iceberg:

iceberg: a large mass of ice floating at sea; usually broken off of a polar glacier
growler: a small iceberg or ice floe just large enough to be hazardous for shipping

iceberg (noun)	growler (noun)
lettuce with crisp tightly packed light-green leaves in a firm head	a small iceberg or ice floe just large enough to be hazardous for shipping
a large mass of ice floating at sea; usually broken off of a polar glacier	a speaker whose voice sounds like a growl