ardu (a) (effort) | strenuous (a) (effort) |
ardu (a) (effort) | laborious (a) (effort) |
ardu (a) (effort) | tough (a) (effort) |
ardu (a) (effort) | hard (a) (effort) |
ardu (a) (effort) | burdensome (a) (effort) |
ardu (a) (effort) | arduous (a) (effort) |
ardu (a) (effort) | difficult (a) (effort) |