adj. 25B6; adjective
a troublesome problem : ANNOYING, irritating, exasperating, maddening, infuriating, irksome, vexatious, vexing, bothersome, tiresome, worrying, worrisome, disturbing, upsetting, niggling, nagging; difficult, awkward, problematic, taxing; informal aggravating; N. Amer. informal pesky.
a troublesome child : DIFFICULT, awkward, trying, demanding, uncooperative, rebellious, unmanageable, unruly, obstreperous, disruptive, badly behaved, disobedient, naughty, recalcitrant; formal refractory.
simple, cooperative.