rubberstamp vs handstamp

rubberstamp is not a noun while handstamp is a noun.

Word	Noun	Adjective	Verb	Adverb
rubberstamp	No	No	Yes	No
handstamp	Yes	No	Yes	No

As verbs, rubberstamp and handstamp are synonyms defined as:

rubberstamp and handstamp: stamp with a rubber stamp, usually an indication of official approval on a document

rubberstamp (noun)	handstamp (noun)
	a stamp (usually made of rubber) for imprinting a mark or design by hand

rubberstamp (verb)	handstamp (verb)
approve automatically	stamp with a rubber stamp, usually an indication of official approval on a document
stamp with a rubber stamp, usually an indication of official approval on a document