hard-and-fast
UK[ˌhɑːd ən ˈfɑːst]US[ˌhɑːrd ən ˈfæst]
adj
(of a rule or distinction) fixed and definitive; not to be set aside or violated.
Etymology
the phrase 'hard-and-fast' originated in nautical terminology during the 19th century. it described a ship that was firmly aground or 'hard and fast' on the shore, completely immobilized and unable to be moved. this literal sense of being rigidly fixed in place was then figuratively extended to describe rules, principles, or distinctions that are similarly rigid, strict, and not subject to change or exception. the logic of the evolution is clear: from a physical state of absolute immobility to an abstract quality of inflexibility and definitiveness.
Analysis
this is a fixed compound adjective formed from two common english words, 'hard' and 'fast', joined by a hyphen and the conjunction 'and'. it functions as a single lexical unit.
Examples
there are no hard-and-fast rules about what to wear to the event.
the distinction between the two categories is not always hard-and-fast.
we need to establish some hard-and-fast guidelines before we proceed.