[from a class of Monty Python characters, poss. with some influence from the 1960s claymation character]
1. An act of minor but conspicuous stupidity, often in gumby maneuver or pull a gumby.
2. [NRL] n. A bureaucrat, or other technical incompetent who impedes the progress of real work.
3. adj. Relating to things typically associated with people in sense 2. (e.g. “Ran would be writing code, but Richard gave him gumby work that's due on Friday”, or, “Dammit! Travel screwed up my plane tickets. I have to go out on gumby patrol.”)