Here, Paul is quoting a Cretian poet and reputed prophet by the name of Epeminides, who lived about 600 years before Christ. Paul confirmed that this deplorable reputation was still valid in his day (Titus 1:13).

Source:

KJV Defenders Study Bible, by Dr. Henry Morris, Ph.D.
Publisher: Thomas Nelson
Language: English
DEF 10 ISBN 0-529-10444-x
DEF 10-1 ISBN 0-529-10445-8