This is the 6171st most frequent German word.
deep
The German word "deep" is "tief" in English, meaning "extending far down or inward."
The word 'tief' is used here as an adjective describing the depth of the lake.
Der See ist sehr tief.
The lake is very deep.
'Tief' in this context is used as an adverb to describe the profound and thorough manner of thinking.
Er dachte tief über das Problem nach.
He thought deeply about the problem.
In this sentence, 'tief' functions as an adjective to describe the intensity and heartfelt nature of her love.