Most -is words are nouns; the adjective skakis 'shaky' is unusual.
Kändis
> 'celeb' is an example of a noun formed from an adjective
(känd '(well-)known').
>
> Kim Bastin
I can add some more argot adjectives, if you are interested:
bakis, having a hangover (< bakfull = "retro-inebriated")
sotis, jealous in love affairs (< svartsjuk, "blacksick"
alluding on "sot", soot)
(Sotis also a common pet name given to a black kitten)
bundis, linked by mutual sympathy or interest (< förbunden,
obligatus)
Svennis is the pet form of the name Sven.
England's soccer coach Sven-Göran Eriksson is always referred to as
Svennis in Sweden.
Skakis is "shaking from fear or shock". Shaky in general
is "skakig" (en skakig färd, a shaky trip).
Lars