seal vs fasten

seal is a noun but fasten is not a noun.

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

seal (noun)	fasten (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

seal (verb)	fasten (verb)
decide irrevocably	make tight or tighter
hunt seals	become fixed or fastened
close with or as if with a seal	cause to be firmly attached
affix a seal to	attach to
make tight; secure against leakage
cover with varnish