On the go

on the go
    adj 1: (of a person) very busy and active; "is always on the go"
    

Go \Go\, n.
   1. Act; working; operation. [Obs.]
      [1913 Webster]

            So gracious were the goes of marriage. --Marston.
      [1913 Webster]

   2. A circumstance or occurrence; an incident. [Slang]
      [1913 Webster]

            This is a pretty go.                  --Dickens.
      [1913 Webster]

   3. The fashion or mode; as, quite the go. [Colloq.]
      [1913 Webster]

   4. Noisy merriment; as, a high go. [Colloq.]
      [1913 Webster]

   5. A glass of spirits. [Slang]
      [1913 Webster]

   6. Power of going or doing; energy; vitality; perseverance;
      push; as, there is no go in him. [Colloq.]
      [1913 Webster]

   7. (Cribbage) That condition in the course of the game when a
      player can not lay down a card which will not carry the
      aggregate count above thirty-one.
      [1913 Webster]

   8. Something that goes or is successful; a success; as, he
      made a go of it; also, an agreement.

            "Well," said Fleming, "is it a go?"   --Bret Harte.
      [Webster 1913 Suppl.]

   {Great go}, {Little go}, the final and the preliminary
      examinations for a degree. [Slang, Eng. Univ.]

   {No go}, a failure; a fiasco. [Slang] --Thackeray.

   {On the go}, moving about; unsettled. [Colloq.]
      [1913 Webster]
    

29 Moby Thesaurus words for "on the go":
      astir, at it, at work, busy, employed, en route, engaged,
      full of business, hard at it, hard at work, in harness, in motion,
      in transit, occupied, on duty, on the bum, on the gad, on the hop,
      on the job, on the jump, on the move, on the road, on the run,
      on the tramp, on the wing, tied up, under sail, under way,
      working