spear thrower vs throwing board

spear thrower and throwing board both are nouns.

Word	Noun	Adjective	Verb	Adverb
spear thrower	Yes	No	No	No
throwing board	Yes	No	No	No

As nouns, spear thrower and throwing board are synonyms defined as:

spear thrower and throwing board: a device resembling a sling that is used in various primitive societies to propel a dart or spear

Other synonyms of spear thrower include dart thrower, throwing stick.

spear thrower (noun)	throwing board (noun)
a device resembling a sling that is used in various primitive societies to propel a dart or spear	a device resembling a sling that is used in various primitive societies to propel a dart or spear