0 being the same colour as the sky when there are no clouds -- أَزْرَق اللّوْن
1 If you say or shout something until you are blue in the face, you are wasting your efforts because you will get no results -- يَنفُخ في قِربة مَقطوعة (مِصر)
2 the colour of the sky when there are no clouds -- اللَّون الأَزْرَق