brakumi

Brakumi is the standard example of the wildcard suffix at work. -Um- has no fixed meaning: it is the one affix Zamenhof left deliberately vague, to be used when a word obviously relates to the root but no other suffix says how. Brako is an arm, so brakumi is to do the arm thing, and everyone understands that as a hug. The same trick gives kolumo (collar, the neck thing) and plenumi (to fulfil, the full thing). Because there is no rule, -um- words have to be learnt one at a time rather than worked out; see The -um wildcard, and word-formation beyond the rules.

The verb is transitive, so it takes the accusative, and brakumo is the hug itself.

Two rivals, both built differently. Ĉirkaŭpreni at rank 2,469 is take-around, the warmer and more literary word, and ĉirkaŭbraki at 2,930 is arm-around, the most physical of the three and the only one you would use of a tree. Brakumi remains the default: it is seven hundred ranks commoner than either, and it is what a speaker reaches for without thinking.