Fetching details from the dictionary...

to struggle in the water; to sink below the surface and become unable to breathe; to (nearly) drown
to indulge in; to lose one's head over something; to be addicted; to wallow in
子どもが深いプールで溺れた。
A child nearly drowned in the deep pool.
彼はギャンブルに溺れている。
He is addicted to gambling.
子供が溺れないよう見守った。
I watched to make sure the child didn't drown.