down with

Preposition

colloquial

(colloquial) Comfortable with; accepting or approving of; okay with / (colloquial) Suffering from (an illness).

Japanese Meaning

（口語）～に同意・受容している、賛成している / （口語）病気にかかっている、体調不良である

If you're down with the plan, we can start tomorrow.

その計画で大丈夫なら、明日始められます。

Sense（1）

(colloquial) Comfortable with; accepting or approving of; okay with

“If I can make your lives easier by staying where I'm supposed to, I'm down with it.”

Sense（2）

(colloquial) Suffering from (an illness).

Everyone's down with the flu, and I'm in the office all by myself.