A chair with supports for the arms or elbows.
To create based on theory or general knowledge rather than data.
To theorize based on analysis of data that was gathered previously; to reflect.
Remote from actual involvement, including a person retired from previously active involvement.
These days I'm an armchair detective.
Unqualified or uninformed but yet giving advice, especially on technical issues, such as law, architecture, medicine, military theory, or sports.
After the American football game, the armchair quarterbacks talked about what they would have done differently to win, if they had been star athletes instead of out-of-shape old men.