Something that is poignant touches you deeply. Watching a poignant YouTube video about baby penguins chasing their mothers, for example, might give you a lump in your throat.
Poignant comes from the Latin pungere “to prick,” the same root as pungent. But something that’s pungent pricks your sense of smell, whereas poignant refers to something that pricks your emotions, especially in a melancholy way. Movie critics might describe a touching portrayal as poignant if there isn’t a dry eye in the house.