Noun-forming suffixes are a type of affix that can be added to the end of a word to create a new noun. The crossword solutions for the term NOUN-FORMING SUFFIX include ATION (5 letters), TUDE (4 letters), TION (4 letters), ION (3 letters), ENCE (4 letters), ANCE (4 letters), ATIVE (5 letters), NESS (4 letters), IER (3 letters), ING (3 letters), and ANCY (4 letters). These suffixes can be used to create nouns from adjectives, verbs, and other nouns. For example, adding '-tion' to the verb 'EDUCATE' creates the noun 'EDUCATION'. Adding '-NESS' to the adjective 'HAPPY' creates the noun 'HAPPINESS'.