to say the least
US /tə seɪ ðə liːst/
UK /tə seɪ ðə liːst/

1.
para dizer o mínimo, no mínimo
used to indicate that one is understating something, or that the reality is more extreme or significant than what is being explicitly stated
:
•
The meeting was chaotic, to say the least.
A reunião foi caótica, para dizer o mínimo.
•
His performance was disappointing, to say the least.
O desempenho dele foi decepcionante, para dizer o mínimo.