No. The word "disregard" has two PREFIXES: dis- and re-. If you mean "Can disregard take a suffix?" the answer is yes: disregarder, disregardful, disregarding.
The suffix is -ly. It is a common adjectival affix that changes noun into an adjective. Something described by a -ly constucted affix is described to have he qualities of the modified noun. The...