The straightforward answer of what is lust in the Bible is that lust falls into the works of the flesh. But also read the following Bible verse:
What is lust in the Bible: The acts of the flesh are obvious: sexual immorality, impurity, and debauchery; idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God. Galatians 5:19
The first explanation of lust is probably the MOST understanding in the sense that acting out lust in a physical way. As in being sexually immoral or having orgies. In normal people's terms that is just spreading your sex around like a tray of food to any and everybody, with no sense of self-control or emotions attached.
Link to original post including other mentioned blog posts and videos:
https://www.sophie-sticatedmom.com/2018/02/13/lust-fix-christian-perspective/
My free ebook with these pieces and more that will teach you how to make a capsule wardrobe you can wear year round: http://eepurl.com/gSn_a5
Shop All My Products: https://sophie-sticatedmom.myshopify.com/
Follow me on Instagram: IG sophie_sticatedmom
Blog: https://sophie-sticatedmom.com
YouTube Channel: https://www.youtube.com/user/TheSlreed84
Podcast: https://sophie-sticatedmom.buzzsprout.com
Want to Donate? paypal.me/sophiesticatedmom
Cashapp $drsophiareed