tranquillize

v 1: make calm or still; "quiet the dragons of worry and fear" syn calm, calm down, quiet, tranquilize, tranquillise, quieten, lull, still ant agitate

2: cause to be calm or quiet as by administering a sedative to; "The patient must be sedated before the operation" syn sedate, calm, tranquilize, tranquillise ant stimulate

Source: WordNet. Princeton University

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