1) Futile 2) Inconsequential 3) Ineffective 4) Not valid 5) Of no force or effect 6) Of no real value 7) Trifling 8) Worthless 1) Nugacious 2) Null 3) Trivial 4) Worthless 
adj. of no force or effect; invalid. Example: a statute which is unconstitutional is a nugatory law.
inconsequential; inoperative; futile; trifling
• (a.) Trifling; vain; futile; insignificant. • (a.) Of no force; inoperative; ineffectual. • (a.) Of no force; inoperative; ineffectual. • (a.) Trifling; vain; futile; insignificant.
Unimportant or having negligible importance.
Nu'ga·to·ry adjective [ Latin nugatorius , from nugari to trifle, nugae jests, trifles.] 1. Trifling; vain; futile; insignificant. 2. Of no force; inoperative; ineffectual. « If all are pardoned, and pardoned as a mere act of clemency, the very substance o...
trifling/worthless 
Of no force or effect; invalid. Example: a statute that is unconstitutional is a nugatory law.
[adj] - of no real value
adjective of no real value; `a nugatory law`
of no real value; trifling; worthless. · of no force or effect; ineffective; futile; vain. · not valid.
[SAT terms] of no real value