Jerk RADICALS mean one thing when used as a SOLO kanji, and another thing when used as a radical inside a bigger kanji.
The classic example of a JERK RAD is 月, which means ‘moon’ when used by itself, but ‘internal organ’ when used as a radical of a bigger kanji : 肺 (lung)、 肝(gallbladder)、腹 (large intestine), etc.
If you know that a certain kanji is a JERK RAD, it’ll help you better guess the meaning of kanji which use that radical.
KANJIDAMAGE