When I'm fearful it's indicative of a lack of trust in God and a small faith in his ultimate provision, regardless of my worldly outcomes.
My definition is along the lines of what Sheepdog said earlier. Fear is the result of me choosing not to FULLY trust God with every aspect of my life. It's so easy to trust God with 99% of your life. I really struggle giving that last 1% to God and entrusting that to Him.Psalm 9:10 "Those who know your name will trust in you, for you, LORD, have never forsaken those who seek you."
Fear is the devil trying to deceive us... If we trust in The Lord our fears will be overcome.
Perfect love casts out all fear. We love Him because He first loved us.