sweetpea vs sweet pea

sweetpea and sweet pea both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetpea	Yes	No	No	No
sweet pea	Yes	No	No	No

As nouns, sweetpea and sweet pea are synonyms defined as:

sweetpea and sweet pea: climbing garden plant having fragrant pastel-colored flowers

Other synonyms of sweetpea include Lathyrus odoratus.

sweetpea (noun)	sweet pea (noun)
climbing garden plant having fragrant pastel-colored flowers	climbing garden plant having fragrant pastel-colored flowers