adjective

insensible

Too slight or gradual to be noticed.

The temperature rises by insensible degrees throughout the afternoon.

Etymology

The negative prefix reverses sensible in its older meaning perceptible to the senses. An insensible change is therefore too slight or gradual to be perceived.

More examples

  • The boundary between the two colors is almost insensible.
  • Small, insensible changes gradually reshape the coastline.
  • The path slopes downward at an insensible angle.

Forms

insensible

insensibly adverb — In a way that escapes notice.

Similar words

imperceptible
Means impossible to detect, not necessarily because change is gradual.
subtle
Means hard to notice but still detectable with attention.