unbutton vs button

unbutton is not a noun while button is a noun.

Word	Noun	Adjective	Verb	Adverb
unbutton	No	No	Yes	No
button	Yes	No	Yes	No

unbutton (noun)	button (noun)
	a round fastener sewn to shirts and coats etc to fit through buttonholes
	an electrical switch operated by pressing
	a device that when pressed will release part of a mechanism
	any artifact that resembles a button
	a specific area or icon in graphical user interface systems that is clicked or pressed in order to select a command or perform an action
	a female sexual organ homologous to the penis
	a round flat badge displaying information and suitable for pinning onto a garment
	any of various plant parts that resemble buttons

unbutton (verb)	button (verb)
undo the buttons of	fasten with buttons
	provide with buttons