likely to be affected by something / easily influenced or tricked; credulous / (medicine) especially sensitive, particularly to a stimulus

(epidemiology) A person who is vulnerable to being infected by a certain disease

plural of susceptible

The quality of being susceptible.

plural of susceptibility

the condition of being susceptible; vulnerability / emotional sensitivity.

(physics) the imaginary component of the admittance of an alternating current circuit

plural of susceptance

susceptible / receptive

plural of susceptivity