English lumps a wide range of harmful speech under the single word gossip, but the Chafetz Chaim's systematic treatment distinguishes several related categories, each with its own rules, and the distinctions do real work in practice.
Rechilut, talebearing, is narrower than lashon hara in one respect and broader in another: it specifically covers carrying information from one party to another, telling someone what a third party said or did concerning them, even when the information is not damaging to reputation, since the harm lies in stirring conflict and suspicion between people rather than besmirching a name as such. The classical case is telling someone "so-and-so said this about you," forbidden essentially regardless of accuracy or mildness, because the relayed information's capacity to damage a relationship, not a reputation, is what the prohibition targets.
Avak lashon hara, the dust of evil speech, covers statements that fall short of direct disparagement but create an unfavorable impression through implication, tone or selective emphasis, such as pointedly praising someone's honesty in a way that implies suspicion about a past transaction. The category exists because the Chafetz Chaim held that the prohibition targets the practical effect of speech on another's standing, and effect can be produced by insinuation as reliably as by direct statement.
Motzi shem ra, the graver offense of outright fabrication covered elsewhere, sits at one end of a spectrum the tradition maps in detail: fabricated harm, accurate harm, harm-neutral talebearing, and merely suggestive insinuation are related but legally distinct wrongs, each attracting its own rulings about what constitutes the offense and what, if anything, excuses it.