1. a situation from which there is no escape
2. a deadlock
3. a standstill or stalemate
USAGE EXAMPLE 1 : The impasse between labour and management was unlikely to be resolved. USAGE EXAMPLE 2 : But he said the United States "holds the key" to breaking the impasse, and could convince Iran to halt its nuclear fuel program by offering security guarantees or a resumption of diplomatic relations with Tehran.