Synonyms: Hide, Discretion, Hide in a crowd
The character knows how to disappear.
He knows not to be noticed in a crowd and how to be forgotten by his past interlocutors and also to hide during a night infiltration.
He also knows basics of disguise, so he can for example try to infiltrate a domain posing as a servant or a guard. His ability to lie in itself is not very convincing, but he knows how to avoid conversations that could unmask him.
He can also, within the limit of humanly possible, navigate stealthily in a building without anyone noticing him.