As adjectives the difference between spellable and smellable
is that spellable is that can be spelled while smellable is that can be detected by smell.
spellable
English
Adjective
(-)
That can be spelled.
Antonyms
* unspellable
smellable
English
Adjective
(-)
That can be detected by smell.
References
* 2007', Günter Radden, René Dirven, ''Cognitive English grammar'', page 284: "Conversion predicates of perception tend to be coded as adjectives: ''visible'', ''audible'', ''palpable'' and ''tangible'', but English lacks adjectives such as '''''*smellable'' and ''*tastable for something that can be smelled or tasted."