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 Gotham has limped on ever since. We are back to finish the job. And this time no misguided idealists will get in the way. Like your father, you lack the courage to do all that is necessary. If someone stands in the way of true justice... ...you simply walk up behind them (..)2005 Batman Begins