Possibly from yumi.
yansumí (Baybayin spelling ᜌᜈ᜔ᜐᜓᜋᜒ) (slang)
- beautiful (especially of one's personality)
- Synonyms: maganda, (slang) yasuwi
- Zorc, R. David, San Miguel, Rachel (1993) Tagalog Slang Dictionary, Manila: De La Salle University Press, →ISBN, page 160