to engage in an inordinately complex task that requires one to establish operating requirements and/or develop capabilities while simultaneously carrying out the functions that these are ultimately intended to support; caution is advised for those finding themselves in a situation where this jargon is apropos, for its jovial nature belies the chaos it portends; the obvious impossibility of such an endeavor is never remarked on, and may indeed be part of the phrase’s charm; similar to build the plane while flying it, which implies an even more frenetic level of activity