Related Clues:

• Friend or foe, e.g.
• Substantive
• Verb, for example
• Life form
• Sentence starter
• Subject, usually
• Something in writing?
• Kind of word
• Whatchamacallit?
• It could be proper
• What you may call it?
• Basic speech part
• Parser's concern
• It may be subject to modification
• Sentence necessity