Here's a question and a few possible answers: 

Q: Sean was an honest person, but his married June, who wasn't honest at all. In fact, who was very what?
Possible A: untruthful, liar, untrustworthy, disloyal, deceitful

Why is "deceitful" an answer aligned with human common sense? 


honest person, but his married june, who wasn't honest at all. deceitful