1. Effort, application, endeavor, exertion imply actions directed or force expended toward a definite end. Effort is an expenditure of energy to accomplish some objective: He made an effort to control himself. Application is continuous effort plus careful attention: constant application to duties. Endeavor means a continued and sustained series of efforts to achieve some, often worthy and difficult, end: a constant endeavor to be useful. Exertion is the vigorous and often strenuous expenditure of energy, frequently without an end: out of breath from exertion.

Did you mean counterfort?