likely to be influenced or harmed
susceptible - prone
If you are ‘susceptible’ to something, you are likely to be influenced or harmed by it. The word implies a character flaw or a particular physical fragility that makes a person vulnerable to certain things, therefore it has negative connotations.
Due to his medical condition, Jack is more susceptible to infections and illnesses.
Con artists rely on the susceptibility of others in order to carry out their deceptions.
The boss isn’t susceptible to flattery, so there’s no point trying to win her over that way.