Astonishing or surprising; something that causes amazement or surprise. It is often used in the negated form ('nicht verwunderlich' — not surprising).
example
Es ist nicht verwunderlich, dass er müde ist, er hat die ganze Nacht gearbeitet.
It is not surprising that he is tired; he worked all night.
Usage tips
Word structure
The adjective is derived from the verb 'verwundern' (to astonish), which in turn comes from the noun 'das Wunder' (miracle/wonder). The ending '-lich' turns it into a quality: something is like a wonder, so it is surprising.
EXAMPLE
Ihre schnelle Genesung war für die Ärzte verwunderlich.
Her quick recovery was surprising to the doctors.
Frequent negation
This word is very often negated: 'nicht verwunderlich' (not surprising) or 'kaum verwunderlich' (hardly surprising). It then means 'logical', 'to be expected', or 'no surprise'.
EXAMPLE
Es ist nicht verwunderlich, dass das Auto kaputt ist; es ist schon 20 Jahre alt.
It is not surprising that the car is broken; it is already 20 years old.
Sentence structure with 'dass'
'Verwunderlich' (surprising) often appears in the construction 'Es ist (nicht) verwunderlich, dass ...' (It is [not] surprising that ...). The subordinate clause with 'dass' then explains exactly what causes the surprise.
EXAMPLE
Es ist verwunderlich, dass er die Prüfung bestanden hat, obwohl er nicht gelernt hat.
It is surprising that he passed the exam even though he did not study.
Compare with
antonym
verwunderlich vs selbstverständlich
self-evident / of course
'selbstverständlich' and 'verwunderlich' are clear opposites. Use 'selbstverständlich' when something is normal, clear, or expected. So it is not surprising. Use 'verwunderlich' when something is surprising and makes you wonder. People also often say 'nicht verwunderlich' (not surprising) when they want to explain that something was actually to be expected. As a guide: if something is normal and clear, it is 'selbstverständlich'. If it makes you surprised or leaves you with questions, it is 'verwunderlich'.
verwunderlich
Seine schlechte Laune im Kurs ist verwunderlich, weil er sonst immer freundlich ist.
His bad mood in class is surprising because he is usually always friendly.
selbstverständlich
In der Schule ist es selbstverständlich, dass man vor dem Essen die Hände wäscht.
At school, it is taken for granted that you wash your hands before eating.