Old English þeofian "to thieve, steal," from þeof (see thief). Rare in Old English, rarer in Middle English, not common until 17c.; perhaps the modern word is a late 16c. re-formation. Thieving (adj.) first attested 1520s.
thickening
thicket
thickness
thickset
thief
thieve
thievery
thievish
thigh
thigmotropism
thilk