Earnest and serious: when should each be used?


I've noticed there's a lot of overlap between the following words meaning
"earnest" or "serious" when talking about a person:

  * まじ
  * 真面目{まじめ}
  * 真剣{しんけん}
  * 本気{ほんき}
  * 正気{しょうき}: (This word really means "sane" I believe, but I'm including it as I think 「正気か？」 can translate to "are you serious?")
  * 素直{すなお}: (I'm not sure whether this word meaning "honest" belongs here I but keep wondering what it's relationship to 真面目{まじめ} is when it means "obedient". I thought there might be some overlap in it's usage, e.g. 「素直な顔」 "obedient face" and 「真面目な顔」 "serious face". It could well be unrelated though.)

Would I be allowed to ask what the differences between these words are and
when they're used?




  * `まじ` colloquial and contracted form of `真面目`.
  * `真面目` 'diligent, serious'
  * `真剣` 'serious, under one's best' implies some tension
  * `本気` 'one's best, mean it'
  * `正気` 'has not lost conscious (due to alchohol, drug, fainting, or extreme situation, etc.)'
  * `素直` 'obedient, open minded'




  * `まじ` colloquial and contracted form of `真面目`.
  * `真面目` 'diligent, serious'
  * `真剣` 'serious, under one's best' implies some tension
  * `本気` 'one's best, mean it'
  * `正気` 'has not lost conscious (due to alchohol, drug, fainting, or extreme situation, etc.)'
  * `素直` 'obedient, open minded'

