leisu = smooth (adjective) (some things Google found for "leisu": an uncommon term; a town in Estonia; user names; appears to be a truncation of the word leisure; Leisu Technology (Quanzhou) Co. Ltd of China sells laser cutters; a subgroup of the Yi people living in Yunnan Province of China; Leisu Scheperle Kirby is a woman who paints murals and does faux finishing)
Word derivation for "smooth" (flat, even):
Basque = leun, Finnish = sileä
Miresua = leisu
My Miresua word starts with "le", the two letters common the Basque and the Finnish words. Like the source words, it has a two vowel combination. The diphthong "ei" in Miresua is pronounced as in the word "eight".