In the Old Testament when you see LORD with all capitals you can safely translate that to mean Yahweh or kyrios. Same goes for many of the Lord references to Jesus. A local pastor puts it this way, if Jesus is LORD in your life it means He calls the shots. He is the architect of our life. He is our coach. He holds the plans and we execute. Your decisions are run through Him and through the filter of His Word before acting. LORD implies reverence and honor. When we refer to Jesus or God as LORD we mean He is above us, owns us, directs us, and is worthy of our submission.

Jesus talks about several people calling him Lord, but not everyone living it.

Matthew 7:21-22, "Not everyone who calls out to me, 'Lord! Lord!' will enter the Kingdom of Heaven. Only those who actually do the will of my Father in heaven will enter. On judgement day many will say to me, 'Lord! Lord! We prophesied in your name and cast out demons in your name and performed many miracles in your name.' But I will reply, 'I never knew you. Get away from me, you who break God's law.'"

This passage tells us two things:

Someone can refer to God as Lord but unless they seek God's steps each day it may be empty of meaning. God will only see insincerity if one calls Him Lord yet insists on living without His influence and direction.
If we call Jesus Lord genuinely, we must obey Him.

What's so beautiful about subjecting ourselves to the LORD of Scripture is that He is full of grace, mercy, and unending love. No better LORD can be found so you joyfully live in reverence to Him. You willingly bow down to Him. If He is Lord over you, He owns you, no exceptions, and you are nothing but proud.

"You are my portion, O LORD; I promise to obey your word." -Psalm 119:57