A ghost can be a lot of things

Name: Steven Crain
Canon: The Haunting of Hill House (TV Series)
Scrubs Color: Navy Blue
Visible Age: 38
Gender: M
Height: 6' 0¾"
Physique: Fit, but not particularly muscular
Complexion: Caucasian, fair
Hygiene: Well-tended
Hair: Dark brown, shortish but artfully shaggy
Eyes: Blue
Accent/Speech: Generic American
Bearing/Demeanor: Calm academic smugness
Gait: Smooth, confident strides