Collocations for justifiable - adj.

be, seem
become
consider sth, think sth
We consider this action justifiable.

completely, entirely, perfectly
commercially, economically
ethically, morally

on the grounds of sth, on the grounds that …, on … grounds
The cutbacks are justifiable on the grounds of cost.
The rule is justifiable on safety grounds.

Justifiable is used with these nouns:
criticism, homicide, pride, reason