i-adjective
susceptible; vulnerable; prone to
Describes something or someone that easily receives an effect, often negative. Used with nouns indicating harm, influence, or conditions.
この素材は湿気を受けやすい。
This material is susceptible to moisture.
彼はストレスを受けやすい体質だ。
He has a constitution prone to stress.
やすい is a suffix meaning 'easy to' or 'likely to', while 受けやすい is a specific adjective meaning 'susceptible' or 'vulnerable'.
Compound of 受ける (ukeru, 'to receive') + やすい (yasui, 'easy to'), literally 'easy to receive'.