Prefix crossword

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Across
  1. 3. some shapes are regular and some are ....
  2. 5. Someone who is untrustworthy
  3. 6. Someone who can't wait
  4. 7. doesn't need help
Down
  1. 1. not essential
  2. 2. Unseen
  3. 4. if something is too heavy it is ....