Quality time 
Time spend with happiness

Queen bee
A woman who has the most power.

Queensberry rules 
An agreement to play in a fair rule.

Queer fish 
A strange person

Queer street
In a real trouble (usually with financial status)

Question of time
Something that will surely happen in the future

Quick on the uptake 
Very smart

Quick buck 
Earn money in an easy way

Quick fix
Problems that can be fix in no time

Quid pro quo 
Give something to favor or payback someone

Quiet as a cat
Very quiet

Quiet as a mouse
Absolutely no noise

Quite so 
Perfectly agree

Quote unquote 
To tell that this quote is copied from the others.