invisible
1. [ adjective ] impossible or nearly impossible to see; imperceptible by the eye
Synonyms: unseeable
Examples:

"the invisible man" "invisible rays" "an invisible hinge" "invisible mending"

Related terms: visible concealed unseen ultraviolet infrared nonvisual camouflaged occult lightless blind imperceptible covert
2. [ adjective ] not prominent or readily noticeable
Synonyms: inconspicuous
Examples:

"he pushed the string through an inconspicuous hole" "the invisible man"

Related terms: conspicuous obscure conspicuousness
Similar spelling:   invisibly
  infeasible
  invigilate
  invasive
  invisibility
  invigilator