Definition of subject to:
(n) :
in a
clause: the word or word group (usually a
noun phrase) that is dealt with. In active clauses with verbs denoting an action, the subject and the actor are usually the same; the main
topic of a paper, work of
art,
discussion, etc
""In the sentence 'The mouse is eaten by the cat in the kitchen.', 'The mouse' is the subject, 'the cat' being the agent.""
(adj) :
pertaining to a person or people who are
ruled by another
"the Roman Empire ruled many subject territories."
(v) :
(followed by to) To cause (someone or something) to undergo a particular experience, especially one that is unpleasant or unwanted