By default, Algolia sets all attributes as searchable, but you are able to define a specific list of “searchable attributes”.
If you do not think the body should be searchable at any point, then at the outset define your list of searchableAttributes and exclude body from that list. You can find the searchable attribute documentation here and here.
If you do think that body should be searchable sometimes, but just not in this instance, you can use restrictSearchableAttributes attributes and exclude body from the list.