The heart
leb (labe)
the heart; also used (figuratively) very widely for the feelings, the will and even the intellect
is deceitful
`aqob (aw-kobe')
in the original sense, a knoll (as swelling up); in the denominative sense (transitive) fraudulent or (intransitive) tracked -- crooked, deceitful, polluted.
above all things and desperately wicked
'anash (aw-nash')
to be frail, feeble, or (figuratively) melancholy -- desperate(-ly wicked), incurable, sick, woeful.
who can know
yada` (yaw-dah')
to know (properly, to ascertain by seeing); used in a great variety of senses, figuratively, literally, euphemistically and inferentially
it