trầm

Etymology
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Verb

 * 1)  to sink (into); to plunge (into)
 * 2)  to keep (something) to oneself (and not give to others)
 * 3)  to make submerged underwater; to drown (something or someone)
 * 4)  to drown oneself

Adjective

 * 1)  deep; low
 * 2)  dull; sluggish
 * 3)  low and flooded