barbwire vs barbed wire

barbwire and barbed wire both are nouns.

Word	Noun	Adjective	Verb	Adverb
barbwire	Yes	No	No	No
barbed wire	Yes	No	No	No

As nouns, barbwire and barbed wire are synonyms defined as:

barbwire and barbed wire: strong wire with barbs at regular intervals used to prevent passage

barbwire (noun)	barbed wire (noun)
strong wire with barbs at regular intervals used to prevent passage	strong wire with barbs at regular intervals used to prevent passage