Possibly from Russian олух (olux) + -o, with a clipping of the second syllable.
This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.
oolo
| Declension of oolo (type 4/koivu, no gradation) | ||
|---|---|---|
| singular | plural | |
| nominative | oolo | oolot |
| genitive | oolon | ooloin, oololoin |
| partitive | ooloa | ooloja, oololoja |
| illative | ooloo | ooloi, oololoihe |
| inessive | ooloos | oolois, oololois |
| elative | oolost | ooloist, oololoist |
| allative | oololle | ooloille, oololoille |
| adessive | oolool | ooloil, oololoil |
| ablative | oololt | ooloilt, oololoilt |
| translative | ooloks | ooloiks, oololoiks |
| essive | oolonna, ooloon | ooloinna, oololoinna, ooloin, oololoin |
| exessive1) | oolont | ooloint, oololoint |
| 1) obsolete *) the accusative corresponds with either the genitive (sg) or nominative (pl) **) the comitative is formed by adding the suffix -ka? or -kä? to the genitive. | ||