Marilyn Vos Savant's 7 October 2001 presents some "Janus words" (words that have two meanings that are opposite) from Richard Lederer's book, Crazy English:
buckle: fasten together, and fall apart (buckle a seat belt, buckle under pressure
clip: separate, and fasten (clip the coupon from the newspaper, clip the coupon to the grocery list)
oversight: supervision, and neglect (he was responsible for oversight of the project, his oversight ruined the project)
qualified: competent, and limited (a qualified candidate, a qualified success)
sanction: approve, and disapprove (sanction the event, impose a sanction on a country)
temper: soften, and strengthen (anger is tempered with reason, steel is tempered by various means)