What is the meaning of Do-?

Alternative form of duo-

a prefix, usually indicating a destination or a completed action or state

impossible, extremely difficult

ill, evil

Rōmaji transcription of ど

verbal prefix

non-, un-

impossible, extremely difficult

ill, evil

pretonic form of dí-

pretonic form of to-

appended to verbs to indicate completion

appended to verbs to indicate addition or furthering a previous process

appended to verbs to indicate addition or approaching a goal

Forms perfective verbs with the following meanings:

1. to finish

   to finish

   up to, to reach

   to add

   appended to verbs to indicate completion

   appended to verbs to indicate addition or furthering a previous process

   appended to verbs to indicate addition or approaching a goal

   un-

   Source: wiktionary.org