Paraplegic works both as a noun and as an adjective. As a noun it names a person who cannot move the lower part of their body, including their legs, usually because of an injury or illness affecting the spinal cord. As an adjective it describes that person or that condition: 'a paraplegic athlete', 'she is paraplegic'.

There is something about the usage that a careful speaker should know. Many disabled people dislike being turned into a label — being called 'a paraplegic' can feel as though the condition has swallowed the whole person. So in careful modern English, especially in news writing and official documents, people prefer 'a person with paraplegia' or simply 'he is paraplegic' over 'he is a paraplegic'. This is not a grammar rule and the noun is certainly not wrong; it is a matter of respect, and you will see both forms in print. Knowing the difference will keep you from sounding cold by accident.

Also note the tone: the word itself is neutral and factual, not sad. Using it with words like 'suffers from' or 'confined to a wheelchair' is what adds the pity, and many wheelchair users find that framing wrong — a wheelchair frees them rather than confines them. 'He uses a wheelchair' is the plain, unloaded way to say it.