Meaning of the word "run deep" in English

What does "run deep" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

run deep

US /rʌn diːp/
UK /rʌn diːp/
"run deep" picture

Idiom

if a feeling, belief, or problem runs deep, it is very strong or serious and has existed for a long time

Example:
The animosity between the two families runs deep.
His love for his country runs deep.