This is the 581st most frequent Estonian word.
põhjus
Reason; cause.
The word "põhjus" is used as a noun meaning 'reason', indicating the cause or explanation for a situation.
Selle põhjus on väga keeruline.
The reason for this is very complex.
In this sentence, "põhjus" is part of the compound "põhjuseta" (without reason), indicating the lack of a cause or justification.
Sa ei tohiks põhjuseta vihane olla.
You shouldn't be angry without a reason.
Here, "põhjus" is used as a noun to denote a justification or rationale for an action.