Stupid English Tricks by KlionskyG

Question 10

Consecutive consonants, part I
Easy as pie: give both English words whose pronunciation (but not necessarily spelling) ends with four consecutive consonant sounds, including voiceless fricatives in the final three positions.

(As an aside: These are two of my favorite words for this reason.)

SIXTHS (-ksθs), TWELFTHS (-lfθs) (I'd prefer twelve sixths of pie to six twelfths)