1 adjective very damagingtubaisteach adj1 c m uit could have disastrous consequencesd'fhéadfadh iarmhairtí tubaisteacha teacht asit was disastrous for the schooltubaiste ba ea é don scoil2 adjective informal very unsuccessfultubaisteach adj1 c m uuafásach adj1 c m uit was a disastrous marriagecleamhnas tubaisteach ba ea é