unseal vs seal

unseal is not a noun while seal is a noun.

Word	Noun	Adjective	Verb	Adverb
unseal	No	No	Yes	No
seal	Yes	No	Yes	No

unseal (noun)	seal (noun)
	any of numerous marine mammals that come on shore to breed; chiefly of cold regions
	a device incised to make an impression; used to secure a closing or to authenticate documents
	fastener consisting of a resinous composition that is plastic when warm; used for sealing documents and parcels and letters
	fastener that provides a tight and perfect closure
	a finishing coat applied to exclude moisture
	an indication of approved or superior status
	a stamp affixed to a document (as to attest to its authenticity or to seal it)
	the pelt or fur (especially the underfur) of a seal

unseal (verb)	seal (verb)
break the seal of	decide irrevocably
	hunt seals
	close with or as if with a seal
	affix a seal to
	make tight; secure against leakage
	cover with varnish