Longman Dictionary of Contemporary English
                    hard-and-fast
                    
                        
                
                                                                    adjective
EXAMPLES FROM CORPUS
▪ Clearly there are dangers involved in drawing a hard-and-fast line between the two principles of participation and identity.
▪ Mrs. Bottomley With respect to my hon. Friend, I do not believe that it is ever possible to cut a hard-and-fast line.
▪ Similarly, it is not possible for him either to give a hard-and-fast definition of Truth.
▪ There is no hard-and-fast divide between water-breathing and air-breathing animals.
                    The Collaborative International Dictionary
                    hard-and-fast
                    
                        
                
                                                                    hard-and-fast \hard-and-fast\ adj. invariable; firmly established; as, hard-and-fast regulations.
Syn: strict.
Wiktionary
                    hard-and-fast
                    
                        
                
                                                                    a. (context idiomatic of rules, etc English) strictly maintained
WordNet
                    hard-and-fast
                    
                        
                
                                                                    adj. (of rules) stringently enforced; "hard-and-fast rules" [syn: strict]
Usage examples of "hard-and-fast".
Hamilton, asked to do the stories, wrote all but three of the 21 novels and novelettes in the series to a hard-and-fast formula.
But life is full of grey areas, places where hard-and-fast rules can't work well, and individual judgment must serve instead.
But life is full of grey areas, places where hard-and-fast rules can’.
But life is full of grey areas, places where hard-and-fast rules cant work well, and individual judgment must serve instead.