Related Clues:

• Lined up
• Aware, with 'in'
• Together
• Nervous, with 'up'
• Well-coordinated
• Tensed, with 'up'
• Atwitter, with 'up'
• Excited, with 'up'
• Harmonious
• Worked (up)
• Tense (with ''up'')
• Jibing
• On the same wavelength
• Working together
• Like a piano