Sinonim undetectable

English Thesaurus

1. barely able to be perceived (adj.all)

similar	:	imperceptible, unperceivable,
definition	:	impossible or difficult to perceive by the mind or senses (adj.all)

2. not easily seen (adj.all)

similar	:	invisible, unseeable,
definition	:	impossible or nearly impossible to see; imperceptible by the eye (adj.all)