cosign - definition and synonyms

verb [transitive] 

Your browser doesn’t support HTML5 audio

/ˈkəʊˌsaɪn/
present tense
I/you/we/theycosign
he/she/itcosigns
present participlecosigning
past tensecosigned
past participlecosigned
  1. to sign a cheque, contract, formal agreement etc together with another person