Outline noun – A line that traces the outer limits of an object or surface. Portrait and outline are semantically related in drawing topic. In some cases you can use "Portrait" instead a noun "Outline". Nearby Words: outlined, outlining
Your character portrait has a white outline that is easily depleted with a few bullets or one sniper shot, but regenerates quickly, sort of like a really weak Halo shield; this is supposed to represent your armor.