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]
(..) She's part of my blood and we understand each other. But you love me. How could I help loving you? You have all the passion for life that I lack. That kind of love isn't enough for a successful marriage... ...for two people as different as we are. Well, why don't you say it, you coward? (..)1939 Gone with the Wind