The meaning of bloodshot eyes is when a persons eyes become red because the small blood vessels that are present on the surface of the eye become enlarged and congested with blood.
Bloodshot eyes happen due to an insufficient amount of oxygen being supplied to the cornea or the tissues covering the eye.
You can get bloodshot eyes from lack of sleep, rubbing your eyes, too much screen time, swimming in swimming pools which chlorine where your eyes are submerged in the water, exposure to smoke etc.
Bloodshot eyes usually go away on their own within a few days to a few weeks depending on the actual cause of your bloodshot eyes.
Having bloodshot eyes is usually nothing serious but if the bloodshot eyes do not get better within a month then you should see an eye doctor or go to urgent care.