Synonyms for Signal:

adj.

extraordinary, outstanding (adjective)
eminent, significant.
important (adjective)
major, central, vital, serious, meaningful, important, significant, crucial, fundamental.
superior (adjective)
quintessential, elite, senior, most, above, uppermost, supreme, eminent, controlling, best, ascendant, sovereign, furthest, chosen, paramount, maximum, leading, foremost, choice, better, zenith, superior, predominant, champion, chief, commanding, master, dominant, crowning, Headmost, king, furthermost, consummate, ruling, A 1.

n.

detail, A to Z, word, fact, report, news, datum, data, information, findings. render, display, make no secret of something, voice, surrender, offer, express yourself, give away, manifest. flourish, action, mime, words, body language, express. button, cameraphone, 4G, calling card, 3G, cell, beeper, answering machine, card, bleeper. mean, proclaim, high sign, signify, represent, stand for, identify, betray. litmus test, foretaste, tip off, preview, promise. cross, jaywalking, grade crossing, crossing, filter, crosswalk, cone, circus, crossroads, green light. alarm (noun)
bell, flare, whistle, buoy, beacon, call, alert, alarm, warning, horn, siren, caution, semaphore, foghorn.
communication (noun)
sign, signaling.
indication (noun)
logo, lighthouse, icon, denotation, token, key, indication, marker, gesticulation, insignia, emblem, legend, notation, pointer, crest, designation, figuration, guidepost, badge, banner, hint, sign, signpost, symbol, logotype.
indication; authorization (noun)
cue, green light, wink, flag, beacon, flare, alert, alarm, token, mark, sign, gesture, nod, high sign.
indicator (noun)
pointer.
motion (noun)
motion.
signal (noun)
point, bespeak, signalize, signaling, sign, indicate, signalise, betoken, impressive.
warning (noun)
alert.
word (noun)
word.

v.

alarm (verb)
frighten, panic, startle, surprise, shock, dismay, scare.
communication (verb)
sign, signalise, signalize.
greet (verb)
curtsy, vociferate, notice, welcome, salute, wave, kowtow, acknowledge, bow, shake hands with, approach, hail, kiss, accost, receive, smile, nod, greet, hug, embrace, salaam.
indicate (verb)
denote, indicate, label, wink, cue, point out, note, guide, stamp, prompt, brand, gesticulate, motion, nudge, designate, tag, shrug, gesture, beckon, mark, notify, ticket, symbolize, point, betoken, flag.
indicate; give a sign to (verb)
semaphore, beckon, signalize, wave, gesticulate, motion.
sound (verb)
cry out, sound.

Other synonyms:

high sign, promise, body language, foretaste. important, litmus test. preview, tip off. flourish. action. Other relevant words:
betray, cameraphone, jaywalking, significant, mean, data, signalize, cell, render, major, flourish, information, preview, meaningful, offer, findings, detail, identify, promise, mime, crucial, green light, report, filter, important, manifest, represent, card, fundamental, proclaim, datum, display, bespeak, words, word, news, fact, cross, crossing, 3G, 4G, button, crosswalk, central, crossroads, action, bleeper, foretaste, circus, serious, voice, signalise, signify, express, impressive, cone, beeper, signaling, surrender, vital.

Usage examples for signal

  1. Signal when you want me back. – From the Car Behind by Eleanor M. Ingram
  2. It was the signal agreed upon between them. – The Triumph of Hilary Blachland by Bertram Mitford
  3. Under the earth was the machine- room of the Signal – The Matador of the Five Towns and Other Stories by Arnold Bennett