1) irreplaceable 2) indispensable
1irreplaceable — index indispensable, inestimable, integral, priceless, vital Burton s Legal Thesaurus. William C. Burton. 2006 …
2indispensable — in·dis·pen·sa·ble /ˌin di spen sə bəl/ adj: having rights so connected to the claims of the parties to an action that the action cannot be adjudicated without affecting those rights see also indispensable party at party Merriam Webster’s… …
3indispensable — Synonyms and related words: bare necessities, basic, bedrock, call for, called for, cardinal, central, compelling, compulsory, crucial, demand, demand for, demanded, desideration, desideratum, essential, essentials, focal, fundamental, imperative …
4irreplaceable — I (New American Roget s College Thesaurus) adj. essential, indispensable (see necessity). II (Roget s IV) modif. Syn. unique, one of a kind, nonrenewable, invaluable; see unique 1 , valuable 1 …
5irreplaceable — adj 1. unique, rare, one of a kind, one and only; priceless, valuable, invaluable, inestimable, precious, worth its weight in gold. 2. indispensable, unexpendable, vital, essential; necessary, requisite, needed, unforgoable …
6Laborem Exercens — was an encyclical written by Pope John Paul II in 1981, on human work. It is part of a larger body of writings known as Catholic social teaching, that trace their origin to Rerum Novarum which was issued by Pope Leo XIII in 1891.External links*… …
7Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
8American Indian Religious Freedom Act — of 1978 Enacted by Congress of the United States Date enacted …
9necessity — ne·ces·si·ty n pl ties 1 a: the presence or pressure of circumstances that justify or compel a certain course of action; esp: a need to respond or react to a dangerous situation by committing a criminal act b: an affirmative defense originating… …
10integral — I adjective basic, cardinal, central, component, constituent, elemental, essential, essential to completeness, fundamental, indispensable, integrant, irreplaceable, necessarius, necessary, needed, needful, prerequisite, primary, required,… …