Autoantonyms

Autoantonyms are words that have two opposing meanings, so that they are effectively their own antonym. My favorites include:

bolt(verb)
• to secure in place
• to dash away suddenly

cleave (verb)
• to adhere; stick together
• to cut apart; divide

rent (verb)
• to lend; lease out
• to borrow; hire

screen (verb)
• to view; show
• to conceal; shield