What does leasing mean in the Bible?

PSALM 4:2 “O ye sons of men, how long will ye turn my glory into shame? how long will ye love vanity, and seek after leasing? Selah.”
PSALM 5:6 “Thou shalt destroy them that speak leasing: the LORD will abhor the bloody and deceitful man.”

Leasing means being loose with the truth, that is, lying.

OXFORD ENGLISH DICTIONARY