growler vs berg

growler and berg both are nouns.

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

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

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

Other hypernyms of growler include iceberg.

growler (noun)	berg (noun)
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