Related Clues:

• One looking
• One who ogles, e.g.
• Watcher
• Watchful one
• Flirtatious fellow
• One gazing
• One who ogles
• Assessor
• Staring sort
• One who watches
• Once-over giver
• One who stares
• Flirt, maybe
• One making a visual assessment
• One checking out?