What is cresant moon?

First of all to correct your spelling. It is 'Crescent'. NOT 'cresant'.

A crescent moon is a phase of the Moon when less than half of the Moon is lit by the Sun , as seen from the Earth. It appears as two circular arcs nesting inside one another; that come to two points (top & bottom). During the Moon's monthly orbit of the Earth, you will see two crescent Moons. One is in the evening , when the Moon is between New Moon and 1st. Quarter. This is a WAXING CRESCENT Moon. The Second is seen in the morning, when the Moon is between Last Quarter and the next New Moon. This is a WANING CRESCENT Moon.

The Moon shows two other faces, between 1st Quarter and Full Moon and between Full Moon and Last Quarter. At these two positions it appears to be not quite circular. It is known as a WAXING/WANINGH GIBBOUS Moon.