1)Sweep under the rug
-The Queen decided to sweep the identity of the prince's real father under the rug.
-The employee who made a mistake swept it under the rug, in the hope his boss would not notice.
-The President wanted to sweep his affair with the intern under the rug.
Definition: To avoid discussing or dealing with (something negative or troubling).
Etymology: This idiom alludes to sweeping dust under the rug, so it wouldn't be seen.
2) Punch above one's weight
-Chris, the personal trainer, told his student not to punch above his weight.
-The small football team punched above their weight by beating Manchester United.
-Jeff punched above his weight by asking Lindsey out on a date.
Definition:
A. To be in a situation that requires powers or abilities that one does not possess.
B. To be temporarily successful in such a situation.
Etymology: From boxing; a fighter who is punching above his weight is fighting an opponent who is heavier and more dominant.