Where does “exstillandus” come from?

exstillandus (Latin) comes from Latin exstillo, from Latin stillo, from Latin -ō, from Proto-Indo-European -ō — Derives nouns from roots.

Definitions

Step	Language	Word	Meaning
1	Latin	exstillo	I trickle out
2	Latin	stillo	I drip, drop, trickle; I distil
3	Latin	-ō	suffixed to nouns or adjectives. Originally a-stem nouns. Later extended to nouns with other stems. Forms regular first-conjugation verbs
4	Proto-Indo-European	-ō	Derives nouns from roots