instantaneityEtymologyFrom instantaneous + -ity. By surface analysis, instant + -aneity.instantaneity means the condition of being instantaneous. Lexicurio rates it Sui generis — a strength score of 87 out of 100.nounThe condition of being instantaneous.“[…] an excited gentleman […] pounded with the knocker on the door of No. 9. As someone did not appear with the instantaneity of a jack-in-the-box, he proceeded to repeat the summons, interspersing it with an occasional "I say!" shouted through the letter-box.”