die Tat
deed / act
An action or act that someone carries out. It refers to something that is done.
Auf große Worte müssen nun auch Taten folgen.
Great words must now be followed by deeds.

deed / act
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deed / act
An action or act that someone carries out. It refers to something that is done.
Auf große Worte müssen nun auch Taten folgen.
Great words must now be followed by deeds.

'Die Tat' (the deed/act) is closely related to the verb 'tun' (to do) and the noun 'der Täter' (perpetrator; person who does something). A 'Tat' is therefore the result of an action, something that was done.
Der Täter konnte nach der Tat unerkannt fliehen.
The perpetrator was able to flee unnoticed after the crime.
There are several fixed expressions with 'Tat'. 'Jemanden auf frischer Tat ertappen' means to catch someone right in the middle of an action, usually a negative one. 'Zur Tat schreiten' means to finally take action after talking.
Der Dieb wurde auf frischer Tat ertappt.
The thief was caught in the act.
In a legal or police context, 'die Tat' almost always refers to a criminal act. Words like 'Polizei' (police), 'Verdächtiger' (suspect), or 'gestehen' (to confess) point to this meaning.
Der Angeklagte hat die Tat vor Gericht gestanden.
The defendant confessed to the crime in court.
The expression 'in der Tat' (indeed) is a fixed expression and functions like an adverb meaning 'tatsächlich' (actually) or 'wirklich' (really). It often appears at the beginning of a sentence or after the verb to confirm a statement.
Das Konzert war in der Tat ein unvergessliches Erlebnis.
The concert was indeed an unforgettable experience.
really
'wirklich' and 'in der Tat' can both confirm a statement or make it stronger. 'wirklich' is very common and flexible in everyday language. You can use it in statements and questions. 'In der Tat' is a fixed expression with the word 'Tat' and means roughly 'indeed' or 'actually'. It sounds somewhat more formal or emphatic and often appears at the beginning of a sentence. The words can be confused because they have a similar effect in some sentences. What matters is this: 'die Tat' by itself normally means an action or deed, often also in connection with the police or the law. Only the expression 'in der Tat' has the meaning of 'wirklich'.

In der Tat ist der Termin heute früher als geplant.
Indeed, the appointment is earlier than planned today.
Meine Kollegin hat die Datei zur Sicherheit wirklich noch einmal geprüft.
To be on the safe side, my colleague really checked the file once more.