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

An interrogative prefix, used to form wh-questions; what, how.

Appears in a few negative imperatives

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

prefix used to express the complete finishing, exhaustion, or cessation of an action: finish, out

prefix used to indicate a large or full measure of an action, often resulting in damage or exhaustion: all over, up

prefix used to indicate movement reaching a specific boundary in space: to, towards, as far as

prefix used to indicate the additional performance of a missing part of an action to achieve completeness

prefix used with reflexive verbs to indicate the successful achievement of a goal or state through effort

Forms perfective verbs with the following meanings:

1. to finish

   to finish

   up to, to reach

   to add

   non-, un-

   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-

   prefix used to express the complete finishing, exhaustion, or cessation of an action: finish, out

   prefix used to indicate a large or full measure of an action, often resulting in damage or exhaustion: all over, up

   prefix used to indicate movement reaching a specific boundary in space: to, towards, as far as

   prefix used to indicate the additional performance of a missing part of an action to achieve completeness

   prefix used with reflexive verbs to indicate the successful achievement of a goal or state through effort

   Source: wiktionary.org