responsible vs undependable

responsible

noun
  • An actor taking on the lesser roles in repertory theatre. 

adj
  • Capable of rational conduct and thus morally accountable for one's behavior. 

  • Able to be trusted; reliable; trustworthy. 

  • Having the duty of taking care of something; answerable for an act performed or for its consequences; accountable; amenable, especially legally or politically. 

  • Answerable to (a superior). 

  • Involving important duties; involving a degree of personal accountability on the part of the person concerned. 

  • Having good judgment in decision-making. 

  • Being a primary cause of a situation or action and thus able to be blamed or credited for it. 

  • In honor shame culture and patronage, the patron of the entity denoted by the prepositional phrase's compliment AKA object, the entity being its client. In this context the patron is usually being described analogously to a rump state that would govern the client, functioning as though it were a complaints department and a disciplinary apparatus by getting involved in any disputes involving the client, e.g. by acid attacking its own client or by taking revenge against the client's accuser. 

undependable

adj
  • Not dependable. 

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