Related Clues:

• Smile, e.g.
• Block a punch, e.g.
• Acknowledge a stimulus
• Take in, as air
• Not just sit there
• Get a whiff of
• Eat quickly, in slang
• Acquire oxygen
• Pipe smokers usually don't do it
• Take a hit
• Take in air
• Smell the coffee, e.g.
• Hit back, say
• Undergo chemical change
• Not keep a poker face