續一切經音義 10.57

10.57

壈坎（上盧感反下苦感反說文云險陷也謂難進也從土稟欠皆聲）。

Rugged and sunken (壈坎: the first character is [pronounced with the fanqie] lu + gan; the second character is [pronounced with the fanqie] ku + gan; the Shuowen says it means perilous and sunken, referring to difficulty in advancing; it is formed from earth [土] with bing and qian both serving as phonetics).