Collocations for worthless - adj.

be, feel, prove, seem | become | make sth
These contradictions made his evidence worthless.

consider sth, discard sth as, dismiss sth as, regard sth as, reject sth as, see sth as
The opinion polls were dismissed as worthless.

absolutely, completely, quite, totally, utterly | almost, virtually | largely

to
The diseased plants are quite worthless to the farmer.