akvumi

The -um- family again, and this one is easy to guess and impossible to derive. Akvo is water. -Um- means "do the obvious thing with this root" and carries no rule at all. So akvumi could in principle have meant to dilute, to swim, to bathe, to flood. It means to water plants, and you know that because somebody told you, not because the suffix said so.

That is exactly the lesson -um- teaches. It is the wildcard: the one official suffix with no fixed sense, put there so the language could name things that did not fit any pattern. Butikumi is to wander round the shops, brakumi to hug, cerbumi to rack your brains, akvumi to water the garden. Each is transparent once learnt and none is predictable in advance. The -um wildcard, and word-formation beyond the rules has the full list and the warning that comes with it.

It is transitive: you akvumas the plants, not the water. The thing you pour is akvo, the tool is an akvumilo (a watering can), and the noun akvumado names the daily round of it - the one Berta does in her garden before the sun gets high.