signless
/ˈsʌɪnlɪs/adjective
1Without a sign; especially (of a building, road, etc.) unmarked by a signpost or notice.
2Chiefly literary. That makes no sign or movement; motionless.
3 Mathematics. Of a number: not distinguished as positive or negative; written without a (plus or minus) sign.
Origin
Mid 17th century; earliest use found in Thomas Fuller (1607/8–1661), Church of England clergyman. From sign + -less.