unsensible

From Middle English unsensible, equivalent to un- +‎ sensible.

unsensible (comparative more unsensible, superlative most unsensible)

1. Not sensible; silly, foolish.
   • 1921, Sheila Kaye-Smith, Joanna Godden‎:

     "Hear, hear," and Joanna passed out of the conversation, for who was going to waste time either taking up or taking down a silly, tedious, foreign, unsensible notion like ploughing grass?...

2. That cannot be sensed; imperceptible.
   • 1921, William Beebe, Edge of the Jungle‎:

     There is no breeze, no slightest shift of air-particles; yet down the gorge comes this cloud,--a cloud unsensible except to nostrils,--eddying as if swirling around the edges of leaves, riding on the air as gently as the low, distant crooning of great, sleepy jungle doves.

3. Out of one's senses; unconscious.

• unsensibly