Synonyms for Signal (same or very similar meaning)
WordNet sense 1 (any communication that encodes a message):
sign, signaling
WordNet sense 2 (making a strong or vivid impression):
impressive
WordNet sense 3 (communicate silently and non-verbally by signals or signs):
signalize, signalise
WordNet sense 4 (be a signal for or a symptom of):
bespeak, betoken, indicate, point
From the ODE community, based on WordNet
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