armchair
n. countable A2 Elementary US //ˈɑɹmˌtʃɛɹ// UK //ˈɑːmtʃeə// arm·chair
n. a comfortable chair with side parts where you can rest your arms.
n. a comfortable, upholstered chair featuring side supports for the occupant's forearms.
He fell asleep in his favorite armchair.
She sat in the velvet armchair by the fireplace to read her book.
The study was furnished with two heavy leather armchairs, positioned to face the large window overlooking the garden.
From arm + chair.
Usage
Often used as a modifier before another noun to describe someone who has theoretical rather than practical experience, such as an 'armchair critic'.