The disjunctive case is a grammatical case in French, where (like other cases) it has a distinct form only for pronouns.

• Moi et lui, nous sommes allés au parc. I and he, we went to the park.
• Nous, nous sommes pour; eux, ils sont contre. We are for; they are against.

It also serves as a sort of prepositional case, in the sense that pronouns marked by preposition take the disjunctive (i.e., avec lui, pour toi, etc).

For non-3rd person verbs in the imperative mood, the disjunctive pronouns are used to mark the direct and indirect objects of a transitive verb, as in the accusative case. So we have écoute-moi (listen to me), dis-moi (tell me). However, in the third person (both singular and plural), the disjunctive is not used. This is likely because French preserves the dative/accusative distinction in the third person, and so use of the disjunctive would result in a loss of information. For example, you say tue-le (kill him), but dis-lui (tell him) -- examples of the accusative and dative, respectively. Note that in this case "lui" is the dative third person singular pronoun, not the disjunctive -- the difference may be seen in the 3rd person feminine, where the disjunctive is "elle" but the dative is still "lui". See also French grammar.