constructive Antonyms

destructive unavailing withering vandalic valueless useless twopenny threepenny subversionary sixpenny sisyphean ruinous retroactive reflexive reactive ravaging pointless as useful as tits on a bull antibiotic freewheeling of no value about as useful as a chocolate teapot not helpful as useful as a chocolate teapot be worthless be of no value useful as a chocolate teapot unhelpful twopenny-halfpenny unconstructive unproductive counterproductive counter-productive shredder in vain dysfunctional negative mordant injurious defective deathlike damaging crushing corrosive corroding caustic cataclysmic cataclysmal blasting baneful