The term 'to no avail' is used to describe an effort that has been unsuccessful or FUTILE. This phrase can be broken down into six crossword solutions: vainly (6 letters), FUTILE (6 letters), INEFFECTIVE (11 letters), idly (4 letters), invain (6 letters), and USELESSLY (9 letters). Vainly means in a way that is without success, FUTILE means having no useful result, INEFFECTIVE means not producing the desired outcome, idly means in an inactive or lazy manner, invain means without success, and USELESSLY means to no effect. All of these words describe an effort that has been unsuccessful or fruitless.