moving spirit

Noun

moving spirit (plural moving spirits)

1. Someone who provides significant impetus or guidance in a given venture, movement, enterprise etc.
   • At the beginning of the year 1804 the most formidable conspiracy which had yet threatened the government and the life of Napoleon was discovered. […] Georges Cadoudal, the Breton peasant, who was the very soul of the royalist party, was the moving spirit.1932, Duff Cooper, Talleyrand, Folio Society, published 2010, page 106
   • We had formed a conspiracy against an unpopular and ignorant teacher. Its moving spirit [translating Seele] was a fellow-student who seems since then to have taken Henry VIII of England as his model.1999, Sigmund Freud, translated by Joyce Crick, The Interpretation of Dreams, Oxford, published 2008, page 163