What are bonding and antibonding moleculs?

In molecules the atomic orbitals of all the atoms are assumed to interfere with each other in the form of waves and depending on the nature of interferences, two molecular orbitals result. The one which results from constructive interference is called bonding molecular orbital and the one which results from destructive interference is called anti-bonding molecular orbital. Obviously anti-bonding MO is of higher energy than Bonding MO.
Electron density is increased for the bonding MO’s in the inter-nuclear region but decreased for the anti-bonding MO’s, Shielding of the nuclei by increased electron density in bonding MO’s reduces inter nuclei repulsion and thus stabilizes the molecule whereas lower electron density even as compared to the individual atom in anti-bonding MO’s increases the repulsion and destabilizes the system.