baby vs infant

baby and infant both are nouns.

Word	Noun	Adjective	Verb	Adverb
baby	Yes	No	Yes	No
infant	Yes	No	No	No

As nouns, baby and infant are synonyms defined as:

baby and infant: a very young child (birth to 1 year) who has not yet begun to walk or talk

Other synonyms of baby include babe.

baby (noun)	infant (noun)
a project of personal concern to someone	a very young child (birth to 1 year) who has not yet begun to walk or talk
a very young mammal
a very young child (birth to 1 year) who has not yet begun to walk or talk
the youngest member of a group (not necessarily young)
an immature childish person
an unborn child; a human fetus
a beloved person; used as terms of endearment

baby (verb)	infant (verb)
treat with excessive indulgence