I think that to take the name of the Lord in vain is to take His name upon yourself frivolously, or as cnorman18 said in
this post, it means to not
carry the name of the Lord in vain. I think that to limit it to cussing is to greatly minimize the gravity of the third commandment.
However, the Bible has much to say regarding what we say, think and do. Consider the following passages:
Philippians 4:8 ESV wrote:Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things
Matthew 12:34 ESV wrote:For out of the abundance of the heart the mouth speaks.
James 3:8-12 ESV wrote:but no human being can tame the tongue. It is a restless evil, full of deadly poison. With it we bless our Lord and Father, and with it we curse people who are made in the likeness of God. From the same mouth come blessing and cursing. My brothers, these things ought not to be so. Does a spring pour forth from the same opening both fresh and salt water? Can a fig tree, my brothers, bear olives, or a grapevine produce figs? Neither can a salt pond yield fresh water.
Ephesians 4:29 ESV wrote:Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear.
Titus 2:7-8 ESV wrote:Show yourself in all respects to be a model of good works, and in your teaching show integrity, dignity, and sound speech that cannot be condemned, so that an opponent may be put to shame, having nothing evil to say about us
1 Peter 1:13-16 ESV wrote:Therefore, preparing your minds for action, and being sober-minded, set your hope fully on the grace that will be brought to you at the revelation of Jesus Christ. As obedient children, do not be conformed to the passions of your former ignorance, but as he who called you is holy, you also be holy in all your conduct, since it is written, "You shall be holy, for I am holy."
1 Peter 3:10 ESV (from Psalm 34:12-13) wrote:For
"Whoever desires to love life
and see good days,
let him keep his tongue from evil
and his lips from speaking deceit;
This is just a sampling. Needless to say, Christians should be cautious about what they speak, for they represent the Lord and should be mindful to not bring dishonor to His name.