1. Totally unlikely
   - impossible, inconceivable, unimaginable

See also: unthinkable

• irreality
• irreclaimable
• irreconcilability
• irreconcilable
• irreconcilableness
• irreconcilably
• irrecoverable
• irrecoverably
• irrecusable
• irredeemable
• irredeemably
• irredenta
• irredentism
• irredentist
• irreducible
• irreducibly
• irrefragable
• irrefutable
• irrefutably
• irregardless
• irregular
• irregularity
• irregularly
• irrelative
• irrelevance