immaculate [LME] For centuries Christian theologians had argued over whether God had preserved the Virgin Mary from the taint of original sin from the moment she was conceived. In 1854 the Vatican declared in favour of the Immaculate Conception and it became a dogma of the Roman Catholic Church. The term involves the earliest, sense of immaculate, ‘free from moral stain’, from Latin in- ‘not’ and macula ‘spot’. The physical sense, ‘spotlessly clean or neat’, dates from the mid 17th century. Similarly, impeccable [M16th] originally meant ‘incapable of sin’, and is still used in this sense in theology, where it has an opposite, peccable [E17th] ‘liable to sin’.