Collocations for unsuitable - adj.

be, prove
make sth, render sth
The size of the rooms made the house unsuitable for conversion into apartments.

consider sth, deem sth, find sth
Many tasks were considered unsuitable for women.

extremely, fairly, very, etc.
highly, most (BrE)
completely, entirely, quite, totally, wholly
manifestly

for

Unsuitable is used with these nouns:
candidate