Know your English !! Part.III

Blue blood: Noble birth, aristocratic descent. The term is a direct translation of the Spanish songre azul:  In Spain, a pale complexion used to be considered a sign of pure breeding—unmixed by Moorish stock from the long Arab occupation of Spain. Such fair skin showed up the bluish veins on the wrist or temple, and so the idea of blue blood developed as a mark of nobility.

Crossing the Rubicon:  Taking a step or making a decision on which there is no going back, and which marks the start of a chain of events:  The Rubicon is the ancient name of a river in northern Italy, believed to be the present day Fiumicino, which Julius Caesar was prohibited from crossing. In 49 BC, however, he forced the river with his army, effectively declaring war in Rome.

Dark horse: unfamiliar competitor or quiet new comer whose abilities remain unknown or untested. The phrase derives from horse racing: the betting public might be ‘in dark’ regarding the speed, stamina, or jumping ability of an unfamiliar runner- a dark horse- and therefore uncertain about the odds.

Devil to pay:  An idiom used to warn that trouble is on the way: the original version shows hot its meaning has changed; the devil to pay and no pitch hot suggests a lack of preparation for some important task – that is, the sailors’ task of sealing with tar the seam (known as ‘the devil’) between the planks of a wooden sailing ship.