Related Clues:

• Like some looks
• Shrewd (Var.)
• Word that can precede the last word of 17-, 24-, 48- and 58-Across
• Ingenious
• Stallone, to friends
• ___ dog
• Like a brainiac
• Like most fast sudoku solvers
• At the head of one's class
• #
• Keen-edged
• Percipient
• Sting a bit
• Tough to outwit
• Like some dogs