salmagundi vs grab bag

salmagundi and grab bag both are nouns.

Word	Noun	Adjective	Verb	Adverb
salmagundi	Yes	No	No	No
grab bag	Yes	No	No	No

As nouns, grab bag is a hyponym of salmagundi; that is, grab bag is a word with a more specific, narrower meaning than salmagundi:

salmagundi (noun)	grab bag (noun)
cooked meats and eggs and vegetables usually arranged in rows around the plate and dressed with a salad dressing	a container from which a person draws a wrapped item at random without knowing the contents
a collection containing a variety of sorts of things	an assortment of miscellaneous items