Synonyms to fastness

acropolis, bastion, beachhead, blockhouse, bridgehead, bunker, castle, citadel, donjon, fasthold, fort, fortress, garrison, garrison house, hold, keep, martello, martello tower, mote, motte, peel, peel tower, pillbox, post, rath, safehold, strong point, stronghold, tower, tower of strength, ward, air speed, celerity, dispatch, expedition, flight, flit, flurry, ground speed, haste, hurry, instantaneousness, knots, lightning speed, miles per hour, precipitation, promptitude, promptness, quickness, rapidity, round pace, rpm, rush, shock wave, snappiness, sonic barrier, sonic boom, sound barrier, speed, speed of sound, speediness, swift rate, swiftness, velocity, aplomb, assurance, balance, balanced personality, composure, confidence, constancy, constraint, control, cool, coolness, discipline, ease, easiness, equability, equanimity, equilibrium, erectness, firmness, homeostasis, imperturbability, independence, invariability, level head, levelheadedness, nerve, nonchalance, orthogonality, perpendicularity, plumbness, plungingness, poise, possession, precipitousness, presence of mind,