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]
(..) Do you want to steer for a while? Thank you. Nobody's ever trusted me with anything before. Is that because of your lack of depth perception? Is it because they're scared of you? I was in the mountains one day... and some campers, Boy Scouts, showed up. And when they saw me, they screamed. (..)2013 Percy Jackson: Sea of Monsters