Related Clues:

• Freezes
• Prepares for a blow
• Past and future
• Shows fear
• Reacts to a threat
• Tightens up
• Verb forms
• Steels
• Tightens, with 'up'
• Grammarian's concerns
• Gets taut
• Factors in conjugation
• Grammar class subjects
• French subjects?
• Gets slick, in a way