What is meant by escape from all signs?

Good will , compassion , equanimity etc are objects of meditation. Good will is used to escape from ill-will. Compassion is used to escape from viciousness. Equanimity is used to escape from passion. All the above ideas are familiar to me and I understand them well. Along the similar lines there is a concept of signless (I guess signless is also an object of meditation). Signless is used to escape from all signs. Following quote from aṅguttara nikāya explains signless : > “Furthermore, there is the case where a monk might say, ‘Although the > signless has been developed, pursued, handed the reins and taken as a > basis, given a grounding, steadied, consolidated, and well-undertaken > by me as my awareness-release, still my consciousness follows the > drift of signs.’ He should be told, ‘Don’t say that. You shouldn’t > speak in that way. Don’t misrepresent the Blessed One, for it’s not > right to misrepresent the Blessed One, and the Blessed One wouldn’t > say that. It’s impossible, there is no way that—when the signless has > been developed, pursued, handed the reins and taken as a basis, given > a grounding, steadied, consolidated, and well-undertaken as an > awareness-release—consciousness would follow the drift of signs. That > possibility doesn’t exist, for this is the escape from all signs: the > signless as an awareness-release.’ I am having difficulty in understanding what are signs? My question is : what is signless (or what is sign) and what is meant by escape from all signs?