Enantiomer Definition:

Enantiomers are pairs of molecules that are not superimposable on their mirror image. i.e they ARE mirror images of each other

Enantiomer Explained:

Every chiral molecule has one non-superimposable mirror image. The original molecule and its mirror image are called enantiomers. Hence, every chiral compound has exactly one enantiomer. The mirror image is, therefore, an entirely different molecule.

Examples –