indisposed to action or exertion; lacking in energy; lazy; indolent

a sluggish disposition.

not acting or working with full vigor, as bodily organs

a sluggish liver.

slow to act or respond

a sluggish car engine.

moving slowly, or having little motion, as a stream.

slow, as motion.

slack, as trade, business, or sales.

adjective

active , alert , energetic , fast , lively , spirited

adjective

apathetic , blah * , comatose , dopey * , down , dragging , draggy , drippy , heavy , hebetudinous , inactive , indolent , inert , laid-back * , languid , languorous , leaden , lethargic , lifeless , listless , lumpish , mooney , off , phlegmatic , pokey * , slack , sleepyheaded , slothful , slow , sluggard , slumberous , stagnant , stiff , sullen , torpid , unresponsive , dull , soft , stupid , stuporous , fainant , idle , shiftless , dilatory , drowsy , laggard , lazy , lymphatic , poky , supine