green light (n.)

• acceptance
• admission
• affirmation
• alarm
• allowance
• approbation
• approval
• authentication
• authorization
• balefire
• beacon
• bell
• blinker
• buoy
• certification
• charter
• confirmation
• consent
• countersignature
• dispensation
• endorsement
• flare
• foghorn
• glance
• go-ahead
• heliograph
• imprimatur
• kick
• leave
• leer
• liberty
• license
• nod
• nudge
• okay
• patent
• permission
• poke
• ratification
• release
• rocket
• sanction
• seal
• semaphore
• sign
• signal
• signature
• signet
• stamp
• subscription
• ticket
• touch
• validation
• visa
• vise
• waiver
• warrant
• wink