貽害無窮

to have disastrous consequences

to present / to bequeath

to have bad consequences

to do harm to / to cause trouble to / harm / evil / calamity

not to have / no / none / not / to lack / un- / -less

endless / boundless / inexhaustible

poor / destitute / to use up / to exhaust / thoroughly / extremely / (coll.) persistently and pointlessly