¹subject

citizen, subject, national mean a person owing allegiance to and entitled to the protection of a sovereign state. citizen is preferred for one owing allegiance to a state in which sovereign power is retained by the people and sharing in the political rights of those people <the rights of a free citizen>. subject implies allegiance to a personal sovereign such as a monarch <the king's subjects>. national designates one who may claim the protection of a state and applies especially to one living or traveling outside that state <American nationals working in the Middle East>.

liable, open, exposed, subject, prone, susceptible, sensitive mean being by nature or through circumstances likely to experience something adverse. liable implies a possibility or probability of incurring something because of position, nature, or particular situation <liable to get lost>. open stresses a lack of barriers preventing incurrence <a claim open to question>. exposed suggests lack of protection or powers of resistance against something actually present or threatening <exposed to infection>. subject implies an openness for any reason to something that must be suffered or undergone <all reports are subject to review>. prone stresses natural tendency or propensity to incur something <prone to delay>. susceptible implies conditions existing in one's nature or individual constitution that make incurrence probable <very susceptible to flattery>. sensitive implies a readiness to respond to or be influenced by forces or stimuli <unduly sensitive to criticism>.

Both liable and apt when followed by an infinitive are used nearly interchangeably with likely. Although conflicting advice has been given over the years, most current commentators accept apt when so used. They generally recommend limiting liable to situations having an undesirable outcome, and our evidence shows that in edited writing it is more often so used than not.