
begründen
to justify
To present and explain the reasons or causes for a statement, opinion, or action.
Sie müssen Ihre Entscheidung für die Kündigung schriftlich begründen.
You must justify your decision to terminate the contract in writing.
to justify / establish
Loading your saved state.

to justify
To present and explain the reasons or causes for a statement, opinion, or action.
Sie müssen Ihre Entscheidung für die Kündigung schriftlich begründen.
You must justify your decision to terminate the contract in writing.

to establish
To bring something new into being, found it, or establish it, for example a company, a tradition, or a partnership.
Die beiden Unternehmer haben gemeinsam eine neue Firma begründet.
The two entrepreneurs established a new company together.
The verb 'begründen' has the prefix 'be-' and is inseparable. So the prefix remains firmly attached to the verb in all sentence forms and is not placed at the end of the sentence.
Er begründet seine Entscheidung ausführlich.
He justifies his decision in detail.
The verb 'begründen' is closely related to the noun 'der Grund' (the reason; the ground). This helps in understanding both meanings: you can give reasons for something (meaning 1), or lay the foundation for something (meaning 2).
Können Sie mir den Grund für diese Änderung nennen?
Can you tell me the reason for this change?
When the reason is stated directly, the preposition 'mit' (with) and the dative are often used. Alternatively, you can use a subordinate clause with 'dass' (that) or 'indem' (by).
Der Minister begründete die neuen Regeln mit der aktuellen Sicherheitslage.
The minister justified the new rules with the current security situation.
In the meaning 'to establish', 'begründen' is often used with abstract concepts that have a beginning. Typical examples are: 'eine Freundschaft begründen' (to establish a friendship), 'eine Tradition begründen' (to establish a tradition), or 'einen Ruf begründen' (to establish a reputation).
Ihre Zusammenarbeit begründete eine lange und erfolgreiche Partnerschaft.
Their collaboration established a long and successful partnership.
to explain / declare
Erklären and begründen both make a connection understandable and can both be used when discussing a decision. Erklären can present the process or cause objectively, while begründen explicitly gives the reasons for a statement or action. Use erklären for a neutral explanation of a cause, and begründen more for a justification.

Die Ärztin begründet, warum sie diese Behandlung heute empfiehlt.
The doctor justifies why she recommends this treatment today.
Die Ärztin erklärt, warum die Behandlung heute länger dauert.
The doctor explains why the treatment is taking longer today.