General terms:
* Word: This is the most general term and doesn't specify a grammatical function.
* Name: This implies something specific that identifies a person, place, or thing.
* Thing: This is very general and doesn't necessarily have a specific grammatical function.
More specific terms:
* Substantive: This refers to a word that functions as a noun, but it's more technical.
* Entity: This suggests something that exists independently, but doesn't necessarily have a grammatical function.
Informal terms:
* Thingamajig: This is a humorous and informal way to refer to a noun.
Ultimately, the best alternative for "noun" depends on the specific context and the desired level of formality.