Flawless means all of these are true:

• Works perfectly
• No noticable flaw
• Has zero scratches or scuffs
• Still in its packaging

Good means all of these are true:

• No crack on screen or body
• Powers on and makes calls
• No major scratches or scuffs

Broken means all of these are true:

• Device still power on
• Cracked screen or body
• Broken or cracked hardware
• Missing buttons or parts