How a thing looks to you the looker.
But you must be careful with atheist evolutionists, because in their phrase 'appearance of design' it means mirage of design, while for a theist it means reality of design as witnessed to by the looker.
The way to get an exact idea of what atheist evolutionists mean by ‘appearance of design’ when they say they don't mean it is just appearance, is to ask them if they be guys: whether they have an appearance of a penis's design or the reality of a penis's design in their penis.
Also with female atheist evolutionists, ask them whether they have an appearance of a vagina's design in their vagina, or the reality of a vagina's design.
Then ask them what exactly do they want to impress people with, in their use of the phrase ‘appearance of design,’ if in their penis or vagina they do not mean just appearance.
Appearance of man, meaning the first time man appeared on earth or in the universe of existence.
Appearance of water in the desert to a man dying from thirst means a mirage of water.
Appearance of design, see definition proper, above.
Appearance of health said by a doctor to a patient, means the doctor cannot see anything medically wrong with the patient even though the patient says he feels miserable.