These words are concerned with carrying out an action. Commit , in this sense, is used mostly in reference to acts which are looked on with disapproval or disfavour: committing a crime; committing suicide. Perpetrate is even more restricted than commit to negative sense, meaning to be guilty of, to perform atrociously or to act deceitfully: to perpetrate a miscarriage of justice; to perpetrate such an inexcusably bad piece of writing; perpetrating a secret plot against the government.

Dispatch and discharge contrast with commit and perpetrate by mainly emphasizing approval for the manner in which a task is done. Dispatch suggests efficiency or speed of performance: dispatching the unpleasant job with extreme care. Discharge suggests the able or faultless performance of a duty or obligation: discharging his promise to work directly with the poor. Sometimes, however, discharge can suggest a literal or minimal rather than an inspired performance: discharging the responsibilities of his job only listlessly and reluctantly.

Do is the least formal and most general of these words and carries no implications whatever about how a task is carried out: doing the job brilliantly; doing greater harm as a private citizen than he had as Prime Minister.