sich zurücklehnen
to lean back
To tilt the upper body backward in order to take a more comfortable, relaxed sitting or lying position.
Er lehnte sich in seinem Sessel zurück und schloss die Augen.
He leaned back in his armchair and closed his eyes.

to lean back
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to lean back
To tilt the upper body backward in order to take a more comfortable, relaxed sitting or lying position.
Er lehnte sich in seinem Sessel zurück und schloss die Augen.
He leaned back in his armchair and closed his eyes.

'Zurücklehnen' (to lean back) is a separable verb. The prefix 'zurück' goes at the end in a main clause. In the infinitive with 'zu', 'zu' goes between the prefix and the verb: 'zurückzulehnen'.
Lehn dich doch einen Moment zurück!
Lean back for a moment!
This verb is always reflexive, which means it is always used with a reflexive pronoun (mich, dich, sich, uns, euch). The pronoun must be adjusted to match the subject.
Ich lehne mich nach einem langen Tag gerne zurück.
I like to lean back after a long day.
The figurative meaning 'entspannen' (to relax) is often recognizable from the context. While the literal meaning usually names a place ('im Stuhl' — in the chair), the figurative meaning is often described through a situation ('nach getaner Arbeit' — after the work is done).
Die Prüfungen sind vorbei, jetzt kannst du dich endlich zurücklehnen.
The exams are over; now you can finally sit back.
In the figurative meaning, the verb is often combined with adverbs or other verbs that express relaxation. Typical phrases are 'sich entspannt zurücklehnen' (to sit back in a relaxed way) or 'sich zurücklehnen und genießen' (to sit back and enjoy).
Nachdem das Projekt erfolgreich war, konnten sich alle zurücklehnen und den Erfolg genießen.
After the project was successful, everyone was able to sit back and enjoy the success.
to wait and see
'abwarten' and 'sich zurücklehnen' can both express that you are not acting actively at the moment. 'abwarten' means that you wait until something happens or becomes clearer before deciding. In a figurative sense, 'sich zurücklehnen' means that you relax and let things happen, often because you have already done everything or cannot change anything anymore. The words can be confused because both sound like calm. However, 'abwarten' is more neutral and matter-of-fact; 'sich zurücklehnen' sounds more like relaxation or passivity.

Nach der Prüfung lehnt sich Anna zurück und genießt den freien Nachmittag.
After the exam, Anna sits back and enjoys the free afternoon.
Die Ärztin will die neuen Werte abwarten, bevor sie die Behandlung ändert.
The doctor wants to wait for the new values before changing the treatment.