teddy bear vs teddy

teddy bear and teddy both are nouns.

Word	Noun	Adjective	Verb	Adverb
teddy bear	Yes	No	No	No
teddy	Yes	No	No	No

As nouns, teddy bear and teddy are synonyms defined as:

teddy bear and teddy: plaything consisting of a child's toy bear (usually plush and stuffed with soft materials)

teddy bear (noun)	teddy (noun)
plaything consisting of a child's toy bear (usually plush and stuffed with soft materials)	a woman's sleeveless undergarment
	plaything consisting of a child's toy bear (usually plush and stuffed with soft materials)