barren, idle, slow

Concise Bible Dictionary:

The words βραδύς, νωθρός, and ἀργός have similar meanings. βραδύς occurs but three times in the N. T.; it differs from the other words in that it is used in a good as well as a bad sense, having only reference to time: 'slow,' in the sense of tardy. The Lord said, "O fools, and slow of heart to believe all that the prophets have spoken," Luke 24:2525Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken: (Luke 24:25); but in Jas. 1:1919Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath: (James 1:19) the exhortation is "be swift to hear, slow to speak, slow to wrath."
νωθρός seems to imply more habitual slothfulness. It occurs but twice in the N. T. The Hebrew saints were "dull of hearing" when they ought by diligence to have been teachers, Heb. 5:1111Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. (Hebrews 5:11); and are exhorted not to be ‘slothful,' but followers of those that inherit the promises. Chap. 6:12. It occurs once in the LXX: it is not fit that one diligent in business should attend on slothful men, Pro22:29.
ἀργός (perhaps from ἀεργός, a neg., and ἔργον, work ') differs from the above in that it is applied to things as well as to persons, and involves blameworthiness. In Matt. 12:3636But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment. (Matthew 12:36), "every ‘idle' word that men shall speak" will have to be accounted for. It is translated ‘idle' in Matt. 20:3, 6, 63And he went out about the third hour, and saw others standing idle in the marketplace, (Matthew 20:3)
6And about the eleventh hour he went out, and found others standing idle, and saith unto them, Why stand ye here all the day idle? (Matthew 20:6)
6And about the eleventh hour he went out, and found others standing idle, and saith unto them, Why stand ye here all the day idle? (Matthew 20:6)
; 1 Tim. 5:13, 1313And withal they learn to be idle, wandering about from house to house; and not only idle, but tattlers also and busybodies, speaking things which they ought not. (1 Timothy 5:13)
13And withal they learn to be idle, wandering about from house to house; and not only idle, but tattlers also and busybodies, speaking things which they ought not. (1 Timothy 5:13)
. In Titus 1:11Paul, a servant of God, and an apostle of Jesus Christ, according to the faith of God's elect, and the acknowledging of the truth which is after godliness; (Titus 1:1)2 The Cretans are said to be slow bellies,' or lazy gluttons.' In 2 Pet. 1:88For if these things be in you, and abound, they make you that ye shall neither be barren nor unfruitful in the knowledge of our Lord Jesus Christ. (2 Peter 1:8), in "using all diligence".... they would be "neither idle nor unfruitful."
more work to be done upon them. Sir C. Brenton translates ‘rough hewn stones.'

Strong’s Dictionary of Greek Words:

Greek:
ἀργός
Transliteration:
argos
Phonic:
ar-gos’
Meaning:
from 1 (as a negative particle) and 2041; inactive, i.e. unemployed; (by implication) lazy, useless
KJV Usage:
barren, idle, slow