Matthew 12:36,37 But I tell you that men will have to give account on the day of judgment for every careless word they have spoken. ³⁷ For by your words you will be acquitted, and by your words you will be condemned."
James 3:2 We all stumble in many ways. If anyone is never at fault in what he says, he is a perfect man, able to keep his whole body in check.

Gossip
(constantly reveling, personal or sensational, facts or rumors) In Joshua 22 Gossip about an altar almost started a war.
You might ask, if the story is true is it still wrong to talk about it?  A mature Christian would ask, What good could come? and what bad?
Proverbs 11:14 Where no counsel is, the people fall: but in the multitude of counselors there is safety. (KJV)
If you need advice and you only use one councilor to confide in, would it still be gossip?
What about only two or three? What about a spouse, pastor, deacon or friend? See Matthew 18:15-17

Murmuring
(half spoken grumbling: bad attitude) 1 Corinthians 10:10 And do not grumble, as some of them did—and were killed by the destroying angel.

Complaining
Numbers 11:1 Now the people complained about their hardships in the hearing of the LORD, and when he heard them his anger was aroused

Nagging
(to irritate by constant scolding, urging, or faultfinding: complaining) Judges 14:17;16:16 Nagging can cause the person who would have stopped not to. It is a kind of stumbling block. Nagging someone to do something usually works but the relationship will be ruined because they will lose all the respect they had for you. Nagging someone to stop something rarely works. It sets up a stumbling block in their mind. Even if they wanted to stop they will not now in order to prove they are in control.
You might say "But isn’t it wrong to say nothing when it could help people?" Yes. That is why you must be led by the Spirit.

Backbiting (to say mean or spiteful things about someone absent)
Slander (false or misleading statements against a person: to defame or malign)
The word "slander" comes from old French meaning a stumbling block. In Romans 3:8 they slandered those who taught grace, in Romans 14:13,21 those who did not observe a Sabbath, and ate certain food, and in  1 Corinthians 8 they slandered those who ate meat that had been sacrificed to Idols.

Using the LORD’s name in vain.
His wrath comes against those who use His name to pretend to prophesy. See Ezekiel 13:1-7.
Using the pulpit to preach rumors (Gossip) is sinning by taking His name in vain.
1 Timothy 1:3-6 ...command certain men not to teach false doctrines any longer ⁴ nor to devote themselves to myths and endless genealogies. These promote controversies rather than God’s work... ⁶ Some have wandered away from these and turned to meaningless talk.
1 Timothy 4:7 Have nothing to do with godless myths and old wives’ tales; rather, train yourself to be godly.
1 Timothy 6:20 ...Turn away from godless chatter and the opposing ideas of what is falsely called knowledge.
Only facts should be presented from the mouth of a Christian. Dwelling on or teaching legalistic speculations or rumors, which is either gossip or slander, sets up a stumbling block that will tempt others to violate their own consciences.
Not taking oaths seriously Matthew 5:33-37 Compare Jephthah to Daniel

Cursing
James 3:9-10 With the tongue we praise our Lord and Father, and with it we curse men, who have been made in God’s likeness. ¹⁰ Out of the same mouth come praise and cursing. My brothers, this should not be.
Peter cursed Simon Magus saying "may your money perish with you in hell" and Paul said let everyone who perverts the gospel be "Anathema." Also remember the curse placed on Jerico. Unless you really mean what you say, don’t say it.

Lying
Ephesians 5:4 Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving.

All quotations taken from the NIV unless otherwise noted.