tantamount
adjective /ˈtæntəmaʊnt/
  /ˈtæntəmaʊnt/
(formal)- tantamount to something having the same bad effect as something else- If he resigned it would be tantamount to admitting that he was guilty.
 Word Originmid 17th cent.: from the earlier verb tantamount ‘amount to as much’, from Italian tanto montare.