i Register
In some senses, stayless is marked as archaic. Watch for register when choosing this word.
adj
Without stays (the item of clothing).
Without stays (nautical)
Without stays (e.g. on a boiler)
Without stop or delay.
1559, William Baldwin (attributed) " […] Richard Neuill of Earle of Warwicke […] ", in The Mirror for Magistrates Among the heauy heape of happy knightes, Whome fortune stald vpon her staylesse stage