code: public Struct getTraitDefinition(final String guid, final String traitName) throws AtlasServiceException{
          JSONObject jsonResponse = callAPIWithBodyAndParams(API.GET_TRAIT_DEFINITION, null, guid, TRAIT_DEFINITIONS, traitName);
  
          try {
              return InstanceSerialization.fromJsonStruct(jsonResponse.getString(AtlasClient.RESULTS), false);
          }catch (JSONException e){
              throw new AtlasServiceException(API.GET_TRAIT_DEFINITION, e);
          }
      }
docs: Get trait definition for a given entity and traitname
  @param guid GUID of the entity
  @param traitName
  @return trait definition
  @throws AtlasServiceException