The term AT FULL SPEED can be described in four different ways, each with five or seven letters. The first is AMAIN, which is an old-fashioned word meaning 'with great speed or force'. The second is APACE, which means 'QUICKLY' or 'at a fast pace'. The third is GALLOPS, which is a verb meaning to move QUICKLY, usually referring to the gait of a horse. Finally, the fourth is LICKETYSPLIT, which is an informal phrase meaning 'very QUICKLY'. All four of these words and phrases describe the same concept: moving at full speed.