A cliff is the edge or top of a rock face (side of a mountain made of rock.)

As Andi said, but it could also be a name for a man: Clifford, or Cliff.

A cliff is a landform consisting of a steep or vertical slope. Usually refers to the cliff when on the coast, but they can also be considered as such those found in mountains, faults and riverbanks. When a coastal cliff in tabular form reaches large bluff is called.