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 he's given me permission to take Sansa as my wife. - (screams) - You'll learn that what I lack in height, - I make up for in appetite. - (screams) and go rehearse our wedding night. - (music playing) - (applause) (..)2016 TvShow: Game of Thrones Title: The Door Season: 6 Episode 5