“THACK” is a valid word. — 14 points Scrabble

chatan informal conversation
hackone who works hard at boring tasks
tackthe heading or position of a vessel relative to the trim of its sails
tachmeasuring instrument for indicating speed of rotation
khatthe leaves of the shrub Catha edulis which are chewed like tobacco or used to make tea; has the effect of a euphoric stimulant

acta legal document codifying the result of deliberations of a committee or society or legislative body
catfeline mammal usually having thick soft fur and no ability to roar: domestic cats; wildcats
hatheaddress that protects the head from bad weather; has shaped crown and usually a brim
katthe leaves of the shrub Catha edulis which are chewed like tobacco or used to make tea; has the effect of a euphoric stimulant

ata highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium
ah
ha(astronomy) the angular distance of a celestial point measured westward along the celestial equator from the zenith crossing; the right ascension for an observer at a particular location and time of day
taa hard grey lustrous metallic element that is highly resistant to corrosion; occurs in niobite and fergusonite and tantalite
kaunknown god; an epithet of Prajapati and Brahma

THACK