Senses
老大 eldest child
the oldest person among siblings or children in a family; the first-born child
老大 boss
the leader of a group, organization, or criminal gang
老大 captain
the master or owner of a sailing vessel; a boatman
老大 very
(colloquial) greatly; extremely. In modern usage, this is primarily used before negative words to express dissatisfaction or reluctance.
老大 old age
(literary) old; of advanced age
老大 titan
a dominant figure or leader in a specific field; a big cheese