having or showing a disposition to avoid exertion; slothful: an indolent person. 2. Pathology. causing little or no pain; inactive or relatively benign: an indolent ulcer that is not painful and is slow to heal.
DNA and RNA are composed of nucleotides that are linked to one another in a chain by chemical bonds, called ester bonds, between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide. The sugar is the 3' end, and the phosphate is the 5' end of each nucleiotide.
This type of bond, in which the electrons tend to spend a lot of time between the two nuclei, is called a covalent bond by chemists. The two electrons involved no longer belong to one atom or the other, but are shared by the two atoms.