Possible Clues:

• Undecorated type?
• Type type
• Like fonts whose T's don't have little feet
• Literally, "without lines"
• Helvetica or Arial, e.g.
• Fairness's wrong for this plain type of face
• Fairness's unusual in this type
• Letter-writing style succeeded - answer is stimulating that's sent back
• A no-frills type
• Like Helvetica, e.g.