deadlock

Short definition from Wiktionary

Noun

1. 1
   A standstill resulting from the opposition of two evenly matched forces; a stalemate or impasse.
2. 2
   An inability to continue due to two programs or devices each requiring a response from the other before completing an operation.
3. 3
   Synonym of deadbolt (“type of lock”).

Verb

1. 1
   To cause or come to a deadlock.