placeholder vs proxy

placeholder and proxy both are nouns.

Word	Noun	Adjective	Verb	Adverb
placeholder	Yes	No	No	No
proxy	Yes	No	No	No

As nouns, placeholder and proxy are synonyms defined as:

Other synonyms of placeholder include procurator.

placeholder (noun)	proxy (noun)
a symbol in a logical or mathematical expression that can be replaced by the name of any member of specified set	a power of attorney document given by shareholders of a corporation authorizing a specific vote on their behalf at a corporate meeting
a person authorized to act for another	a person authorized to act for another