Question:

The suffix –ation commonly forms nouns from verbs, e.g., converse and conversation, confront and confrontation, revoke and revocation, celebrate and celebration, etc. The suffix –ness commonly forms nouns from adjectives, e.g., happy and happiness, kind and kindness, dark and darkness, etc.; as does the suffix –ity, e.g., formal and formality, sensitive and sensitivity, gay and gaiety, etc. However, the suffix –id commonly forms adjectives from nouns, e.g., candor and candid, livor and livid, rabies and rabid, rigor and rigid, etc.