problem vs subject

problem

adj
  • Causing a problem; problematic; troublesome. 

  • Difficult to train or guide; unruly. 

noun
  • A difficulty that has to be resolved or dealt with. 

  • A puzzling circumstance. 

  • A set of moves required to complete a climb. 

  • A question to be answered, schoolwork exercise. 

  • Objection. 

  • Difficulty in accepting or understanding or refusal to accept or understand. 

subject

adj
  • Likely to be affected by or to experience something. 

  • Placed or situated under; lying below, or in a lower situation. 

  • Conditional upon something; used with to. 

  • Placed under the power of another; owing allegiance to a particular sovereign or state. 

noun
  • A being that has subjective experiences, subjective consciousness, or a relationship with another entity. 

  • The variable in terms of which an expression is defined. 

  • The main topic of a paper, work of art, discussion, field of study, etc. 

  • The main theme or melody, especially in a fugue. 

  • A person ruled over by another, especially a monarch or state authority. 

  • A particular area of study. 

  • A citizen in a monarchy. 

  • In a clause: the word or word group (usually a noun phrase) about whom the statement is made. In active clauses with verbs denoting an action, the subject and the actor are usually the same. 

  • That of which something is stated. 

  • An actor; one who takes action. 

  • A human, animal or an inanimate object that is being examined, treated, analysed, etc. 

verb
  • To make subordinate or subservient; to subdue or enslave. 

  • To cause (someone or something) to undergo a particular experience, especially one that is unpleasant or unwanted. 

How often have the words problem and subject occurred in a corpus of books? (source: Google Ngram Viewer )