Entry 1 sense Webster, 1913 Fidejussor · Fi·de·jus·sor · IPA /ˌfaɪdɪˈd͡ʒʌsə(ɹ)/ 01 n. A surety; one bound for another, conjointly with him; a guarantor. 1. A surety; one bound for another, conjointly with him; a guarantor.(Civil Law)