4. (adj)signal notably out of the ordinary "the year saw one signal triumph for the Labour party"
5. (verb)sign, signal, signalize, signalise communicate silently and non-verbally by signals or signs
"He signed his disapproval with a dismissive hand gesture"; "The diner signaled the waiters to bring the menu"
6. (verb)bespeak, betoken, indicate, point, signal be a signal for or a symptom of
"These symptoms indicate a serious illness"; "Her behavior points to a severe neurosis"; "The economic indicators signal that the euro is undervalued"