Antonyms of adj painless

2 senses of painless

Sense 1
painless -- (requiring little hard work or exertion; "a painless solution to the problem")

INDIRECT (VIA easy) -> difficult, hard -- (not easy; requiring great physical or mental effort to accomplish or comprehend or endure; "a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "why is it so hard for you to keep a secret?")

Sense 2
painless (vs. painful) -- (not causing physical or psychological pain; "painless dentistry")

painful (vs. painless) -- (causing physical or psychological pain; "worked with painful slowness")
        => aching, achy -- (causing a dull and steady pain; "my aching head"; "her old achy joints")
        => agonized, agonised -- (expressing pain or agony; "agonized screams")
        => agonizing, agonising, excruciating, harrowing, torturing, torturous, torturesome -- (extremely painful)
        => biting, bitter -- (causing a sharply painful or stinging sensation; used especially of cold; "bitter cold"; "a biting wind")
        => chafed, galled -- (painful from having the skin abraded)
        => poignant -- (keenly distressing to the mind or feelings; "poignant anxiety")
        => itchy -- (causing an irritating cutaneous sensation; being affect with an itch; "he had an itchy toe from the mosquito bite")
        => racking, wrenching -- (causing great physical or mental suffering; "a wrenching pain")
        => saddle-sore -- ((of a rider) sore after riding a horse)
        => sensitive, sore, raw, tender -- (hurting; "the tender spot on his jaw")
        => traumatic -- (psychologically painful;"few experiences are more traumatic than losing a child";)

Similarity of adj painless

2 senses of painless

Sense 1
painless -- (requiring little hard work or exertion; "a painless solution to the problem")
       => easy (vs. difficult) -- (posing no difficulty; requiring little effort; "an easy job"; "an easy problem"; "an easy victory"; "the house is easy to heat"; "satisfied with easy answers"; "took the easy way out of his dilemma")

Sense 2
painless (vs. painful) -- (not causing physical or psychological pain; "painless dentistry")
       => pain-free, unpainful -- (not accompanied by pain sensations; "pain-free surgery")
          Also See-> harmless#1