Nonchalance.
Carelessness, heedlessness, indifference, or casual unconcern.
The degree of response of an instrument to a change in an input signal.
The degree of response of a film etc. to light of a specified wavelength.
The ability of an organism or organ to respond to external stimuli.
The quality or state of being sensitive; sensitiveness.
Vulnerability to medical treatment: Synonym of susceptibility.
The probability, in a binary classification test, of a true positive being correctly identified.