When a person is demonstrative, they do not hide that they care. They hug. They say “I love you.” They hold your hand where other people can see. The word is about showing the feeling, not about how big the feeling is — a quiet person can love you just as much. Families and cultures differ here: some are demonstrative all the time; in others, love stays more private, and a demonstrative friend can feel like a lot. You will hear it about parents, partners, and whole groups: “She’s very demonstrative with her kids.” It is not a rude word, though some older speakers use it with a small raised eyebrow, as if the showing is a bit much. Though actually, the same spelling is also a grammar word for this, that, these and those — that is a different job, about pointing, not about love.