[un.der.neath] prep [ME undernethe, prep. & adv., fr. OE underneothan, fr. under + neothan below--more at beneath] (bef. 12c) 1 a: directly beneath "write the date ~ the address" b: close under esp. so as to be hidden "treachery lying ~ a mask of friendliness" "wore a swimsuit ~ his slacks"
2: under subjection to
[2]underneath adv (bef. 12c) 1: under or below an object or a surface: beneath
2: on the lower side -- underneath adj