The apparent reversal of motion of planets against the backdrop of fixed stars is called

The planets move eastward against the background of fixed stars with the exception of Venus, Uranus and Pluto moving westward as seen in Earth's sky. This apparent retreating movement is called Retrograde motion. It is illusion created by Earth's movement going by outer planets in their respective orbits.

Apparent retrograde motion

Explanation:

Planets travel in an aparent irregular way. Their movement along the space from west to east, is interrupted during brief intervals of time by an apparent retrograde motion from east to west. This apparent retrograde motion is preceded by a speed decrease until planet stops, then, it goes back to a stationary position again and resumes its direct motion from west to east.