adjective
thorough, thoroughly
B1
'gründlich' means thorough (adjective) and thoroughly (adverb). It’s gradable: comparative gründlicher, superlative am gründlichsten. Opposite: oberflächlich. Standard adjective declension applies in attributive position; used to describe careful, exhaustive actions or inspections. Not a participle or reflexive verb; common in spoken and written German.
Examples
Er hat den Bericht gründlich gelesen, bevor er ihn unterschrieb.
He read the report thoroughly before signing it.
Die Reinigung war sehr gründlich und das Haus sieht wie neu aus.
The cleaning was very thorough and the house looks like new.
Der Arzt untersuchte den Patienten gründlich, weil zuvor Symptome aufgetreten waren, die eine genaue Diagnose erforderten.
The doctor examined the patient thoroughly because symptoms had appeared earlier that required an accurate diagnosis.
Details
Mnemonics
picture someone scrubbing every corner until it's perfectly clean
sounds like 'ground-lich' — think of cleaning down to the ground
Notes
Can be used attributively (ein gründlicher Check) or adverbially (etwas gründlich tun). Comparative: gründlicher, Superlative: am gründlichsten.