I. arm ‧ chair 1 /ˈɑːmtʃeə, ˌɑːmˈtʃeə $ ˈɑːrmtʃer, ˌɑːrmˈtʃer/ BrE AmE noun [countable]
a comfortable chair with sides that you can rest your arms on
II. arm ‧ chair 2 /ˈɑːmtʃeə $ ˈɑːrmtʃer/ BrE AmE adjective
armchair traveller/fan etc someone who talks or reads about being a traveller, or watches sport on television but does not have any real experience of doing it:
Her books about her adventures give enjoyment and inspiration to armchair travellers.
Armchair fans will have to pay extra to watch the best games live.