guarantee
From LSJ
English > Greek (Woodhouse)
verb transitive
promise: P. and V. ὑπισχνεῖσθαι, P. ὑποδέχεσθαι, V. ὑπίσχεσθαι; see promise.
give security: P. and V. πίστιν διδόναι or πιστἄ διδόναι.
substantive
P. and V. πίστις, ἡ, πιστά, τά, ἐγγύη, ἡ.
promise: P. and V. ὑπόσχεσις, ἡ.
one who guarantees: Ar. and P. ἐγγυητής, ὁ.