That cannot be perceived; imperceptible.(adjective)
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Use "imperceivable" in a sentence
"There's an old management trick: huff about unknown and imperceivable "errors" and "mistakes" and just not "getting it" to keep product to be repurposed elsewhere flowing."
"And she knew that to him they were alone together in a world where the high-rouged row of ballet faces and the massed whines of the violins were as imperceivable as powder on a marble Venus."
"The writer in relation to the nature of perceivable reality and what is beyond - imperceivable reality"