In order for you to understand what that is, you must first understand what sexual reproduction is. Sexual reproduction is where two creatures both contribute DNA to create a new creature. Asexual reproduction simply means reproduction that isn't sexual. So basically, it's when a creature reproduces on it's own, rather than two creatures reproducing.
Asexual reproduction is when there is a cell division occurs by the process of mitosis. In this way , the daughter cells have the diploid no. Of chrimosomes ( identical to parent cell). In asexual reproduction,, all the offsprings share the identical traits as parents