You searched for:
“imperceptibly”
imperceptibly (adverb), more imperceptibly, most imperceptibly
Relating to something that is too small to be detected or too little to be perceived: No one noticed when Henry moved imperceptibly out the door to check if there was any mail in his box.
This entry is located in the following unit:
cap-, cip-, capt-, cept-, ceive, -ceipt, -ceit, -cipient
(page 7)