Possible Clues:

• Unpretentious character on the staff
• Spontaneous individual assured of success
• Not artificial or imitation
• __ gas
• Eccentric aunt carrying type of bomb in both hands — it's normal
• Someone sure to succeed but isn't sharp
• Artificial's opposite
• Ebbing brown river, pure
• 7 or 11 on the opening roll at craps is an example of a ___ number
• Racing certainty with no airs