James Strong - Słownik Języka Greckiego

Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity^G1505 and truth.
KJV 1 Kor 5:8

For our rejoicing is this, the testimony of our conscience, that in simplicity and godly sincerity,^G1505 not with fleshly wisdom, but by the grace of God, we have had our conversation in the world, and more abundantly to you-ward.
KJV 2 Kor 1:12

For we are not as many, which corrupt the word of God: but as of sincerity,^G1505 but as of God, in the sight of God speak we in Christ.
KJV 2 Kor 2:17