the tip of the iceberg
US /ðə tɪp əv ði ˈaɪs.bɜːɡ/
UK /ðə tɪp əv ði ˈaɪs.bɜːɡ/
1.
only a small, visible part of a much larger, hidden problem or situation
:
•
The recent scandal is just the tip of the iceberg; there's much more corruption to uncover.
•
His current financial troubles are just the tip of the iceberg of his deeper debt problems.