noun

• The quality or state of being sensitive; sensitiveness.
• (biology) The ability of an organism or organ to respond to external stimuli.
• (biology, medicine, of a pathogen) Vulnerability to medical treatment: Synonym of susceptibility.
• (statistics) The probability, in a binary classification test, of a true positive being correctly identified.
• (electronics) The degree of response of an instrument to a change in an input signal.
• (photography) The degree of response of a film etc. to light of a specified wavelength.