Blessed are those whose way is blameless, who walk in the law of the Lord! Blessed are those who keep his testimonies, who seek him with their whole heart, who also do no wrong, but walk in his ways! - Psalm 119:1-3 (ESV)
The etymology of the word is often understood as "lacking worth", from two common words: beli- (בְּלִי "without-") and ya'al ( יָעַל "to be of value").
A worthless person, a wicked man, goes about with crooked speech, winks with his eyes, signals with his feet, points with his finger, with perverted heart devises evil, continually sowing discord; therefore calamity will come upon him suddenly; in a moment he will be broken beyond healing. - Proverbs 6:12-15 (ESV)
Image: 'Enter Scorpius' by Al Wiggins Jr.