A problem is a question or matter involving doubt, uncertainty, or difficulty. A conundrum is a particularly puzzling or complex question or problem. In some cases, conundrum refers to a riddle that involves a pun or play on words (what is black and white and red all over? A newspaper!). However, nowadays conundrum more commonly refers to a riddle of the less literal variety. If you find yourself stumped in a perplexing situation—look out, you may be in a conundrum!

Pretend and feign both deal with attempting to create a false appearance. However, feign suggests a degree more sophistication in the art of deception. To feign interest in something is to represent your level of interest fictitiously. Unlike pretend, feign is not used to talk about playful make believe where all parties are privy to the pretense. On the contrary, feign is used in situations where one party aims to convince another of something untrue, as an emotional state or physical condition.

The adjective pensive means “dreamily or wistfully thoughtful.” Someone who is in a pensive mood may be given to contemplation or reflection. While thoughtfulness is central to the meaning of pensive, the word itself suggests more feeling than the adjective thoughtful—and it is not used to convey consideration for others in the same way that thoughtful sometimes is. The attention of someone who is pensive is directed inward rather than outward.