iceberg vs berg

iceberg and berg both are nouns.

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

As nouns, iceberg and berg are synonyms defined as:

iceberg and berg: a large mass of ice floating at sea; usually broken off of a polar glacier

iceberg (noun)	berg (noun)
lettuce with crisp tightly packed light-green leaves in a firm head	a large mass of ice floating at sea; usually broken off of a polar glacier
a large mass of ice floating at sea; usually broken off of a polar glacier