Covalent radius (r_c) is the half of the distance between the two nuclei of the atoms bonded by the covalent bond. (see figure below)

Figure 1: Covalent radius

In the solid state, the half of the distance measured between two non-bonding atoms of a homonuclear diatomic molecule is called van der Waals radius (r_v).

Figure 2: Van der Waals radius

Clearly, van der Waals radius is larger than the covalent radius.