stop operating or functioning; "The engine finally went"; "The car died on the road"; "The bus we travelled in broke down on the way to town"; "The coffee maker broke"; "The engine failed on the way to town"; "her eyesight went after the accident"
prove insufficient; "The water supply for the town failed after a long drought"
disappoint, prove undependable to; abandon, forsake; "His sense of smell failed him this time"; "His strength finally failed him"; "His children failed him in the crisis"
become bankrupt or insolvent; fail financially and close; "The toy company went bankrupt after the competition hired cheap Mexican labor"; "A number of banks failed that year"
fall short in what is expected; "She failed in her obligations as a good daughter-in-law"; "We must not fail his obligation to the victims of the Holocaust"
fail to get a passing grade; "She studied hard but failed nevertheless"; "Did I fail the test?"
judge unacceptable; "The teacher failed six students"
be unsuccessful; "Where do today's public schools fail?"; "The attempt to rescue the hostages failed miserably"
fail to do something; leave something undone; "She failed to notice that her child was no longer in his crib"; "The secretary failed to call the customer and the company lost the account"
keep in one's mind; "I cannot retain so much information"
secure and keep for possible future use or application; "The landlord retained the security deposit"; "I reserve the right to disagree"
allow to remain in a place or position; "We cannot continue several servants any longer"; "She retains a lawyer"; "The family's fortune waned and they could not keep their household staff"; "Our grant has run out and we cannot keep you on"; "We kept the work going as long as we could"
hold within; "This soil retains water"; "I retain this drug for a long time"
a statement acknowledging something or someone; "she must have seen him but she gave no sign of acknowledgment"; "the preface contained an acknowledgment of those who had helped her"
at or near or toward the stern of a ship or tail of an airplane; "stow the luggage aft"; "ships with square sails sail fairly efficiently with the wind abaft"; "the captain looked astern to see what the fuss was about"