1. equivalent in seriousness to; virtually the same as
Usage: usually followed by ‘to’

Examples

• His silence was tantamount to an admission of guilt.
• The new policy is tantamount to censorship.
• Refusing to help would be tantamount to betrayal.
• The delay was tantamount to a cancellation.
• Her behavior was tantamount to insubordination.
• The proposal is tantamount to starting over completely.