A multirole combat aircraft (MRCA) is a military airplane designed for more than one purpose. A multirole fighter is a multirole combat aircraft that can be used to attack enemy airplanes.
The term "multirole" is the ability for the airplane to perform more than one task or combat role. Many times airplanes will be designed for one task, and later someone will make small changes to the airplane to perform a different task. For example, the F-15 Eagle was first designed as an air superiority fighter to destroy other enemy fighters. Many years later its designers made changes to allow it to carry bombs and missiles and attack targets on the ground.
There are many roles that combat airplanes may fill: