Rigidly formal is a term used to describe a situation or person that is very strict and follows a set of rules without any flexibility. The crossword solutions for this term are PRIM (4 letters), STARCHY (7 letters), and STIFF (5 letters). PRIM is an adjective meaning excessively proper or primly correct. STARCHY is an adjective meaning stiffly formal or rigidly conventional. STIFF is an adjective meaning not able to be bent or moved easily. All three words describe the same concept of being rigidly formal.