The term 'Fastidious to a Fault' can be summarized by two crossword solutions: 'PRISSY' (6 letters) and 'ANAL' (4 letters). PRISSY is an adjective used to describe someone who is excessively concerned with neatness and propriety, often to the point of being overly fussy or finicky. ANAL is an adjective used to describe someone who is excessively orderly and attentive to detail, often to the point of being overly strict or rigid. Together, these two words describe someone who is fastidious to a fault, meaning they are so concerned with neatness and order that it becomes a problem.