growler vs iceberg

growler and iceberg both are nouns.

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

As nouns, iceberg is a hypernym of growler; that is, iceberg is a word with a broader meaning than growler:

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

Other hypernyms of growler include berg.

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