Singular

ainutlaatuinen

(being the only one of a kind)

erinomainen

(distinguished by superiority)

harvinainen

(being out of the ordinary)

kummallinen

(being out of the ordinary)

merkillinen

(being out of the ordinary)

omituinen

(being out of the ordinary)

singulaarinen

(linear algebra: of matrix: having no inverse)

singulaarinen

(linear algebra: of transformation)

tavaton

(distinguished by superiority)

uniikki

(being the only one of a kind)

yksiköllinen

(grammar: referring to only one thing)

yksittäinen

(being only one of larger population)

yksikkö

(grammar: form of a word that refers to only one thing)