IPA: /əˈseɪləbl/
KK: /əˈseɪləbəl/
Something that cannot be defended or protected from attack or criticism.
The castle was assailable from the north side due to the lack of a wall.
Assailable is formed from "assail" (from Old French *assailir*, meaning to attack) and the suffix "-able" (meaning capable of). The word "assailable" means capable of being attacked or assaulted.
Think of being 'capable of being attacked' — 'assail' means to attack, and '-able' means capable.