They called it a comet, 'for lack of' a better term/word. [=because they could not think of a better term/word for it]
His honesty, or 'lack thereof', is the real problem. [=the real problem is his lack of honesty]
There was 'no lack of' interest in the proposal. [=there was much interest in the proposal]
(..) and Moscow and the third bloody world war. Look, the Minister's very pleased with your progress so far. He's less pleased, though, with the lack of progress with our American cousins. You see, in their eyes, you're still a leaky ship. Yes? (..)2011 Tinker Tailor Soldier Spy