perturbi

Check the seam before you trust it. Per is a real Esperanto preposition, "by means of", and it is used as a prefix. Turbo is a real Esperanto word too: a spinning top, the child's toy. So perturbi offers you a decomposition, and the decomposition gives you "to do something by means of a spinning top", which is not what the word means. There is no verb turbi in Esperanto at all. Both halves exist, neither half is the right half, and that is exactly the trap ferdeko sets twelve ranks earlier in this same band.

The Latin, on the other hand, decomposes properly. Perturbare is per- as an intensifier plus turbare, to stir up, and turbare is from turba, a disorderly crowd. So the ancestral picture is a crowd being stirred until it is a mob, and every English descendant keeps some of it: perturb, turbulent, disturb, and trouble, which came the long way round through French. Esperanto's turbo, the spinning top, is from the same Latin turbo in its other sense, a whirlwind or a whirling thing, so the two words are cousins after all. They just are not parts of each other.

Strength, and how it differs from ĝeni. Ĝeni is to bother or inconvenience: somebody talking behind you in a cinema ĝenas you. Perturbi is stronger and structural. It is what happens to a system, a schedule, a meeting, an orbit or a state of mind when something knocks it out of its proper order. A perturbo in astronomy is the deviation of a body's orbit caused by another body, which is the technical use the word carries in several languages; in a weather report it is a disturbance. If you would say "disrupt" or "throw into disorder" in English, perturbi is right; if you would say "annoy", ĝeni is.

The family. Perturbo is the disturbance itself, perturbiĝi is to become disordered, and neperturbebla is imperturbable, which is a pleasing thing to be able to build. Malordo covers plain disorder as a state, and ordigi is to put back in order, which is the repair the verb calls for. And note the transitivity: perturbi always takes an object, so "the meeting was disrupted" is la kunveno estis perturbita or la kunveno perturbiĝis, never la kunveno perturbis. The transitivity article explains why Esperanto is stricter about this than English.