Synonyms for Overactive:

n.

harmful, perilous, ruinous, risky, dangerous, injurious, hazardous, disastrous, damaging, unsafe. imaginative, visionary, run riot, imaginings, creativity, thinkable, originality, imagination, creative, a vivid imagination. overactive (noun)
hyperactive, active.

Other synonyms:

adj.
hyperactive.
n.
hyperactive.