comfy, comfortable, cushy, facile, lenient, easygoing, gentle, leisurely, prosperous, pleasing, more...

difficult, hard, challenging, complex, arduous

simple, basic, routine, everyday, ordinary, common, more...

midshipman, lady, and, dead, more, geography, observed, pct, quick, general, free

"duck soup!",   child's play,,   child's play,   low effort,   "piece of cake!",   not difficult,   not hard,   no effort,   too simple,   not hard-fought,   it's a snap,   no fuss