slogan vs motto

slogan and motto both are nouns.

Word	Noun	Adjective	Verb	Adverb
slogan	Yes	No	No	No
motto	Yes	No	No	No

As nouns, slogan and motto are synonyms defined as:

slogan and motto: a favorite saying of a group, organization or individual

Other synonyms of slogan include catchword, shibboleth.

slogan (noun)	motto (noun)
a favorite saying of a group, organization or individual	a favorite saying of a group, organization or individual