weeder vs weed puller

weeder and weed puller both are nouns.

Word	Noun	Adjective	Verb	Adverb
weeder	Yes	No	No	No
weed puller	Yes	No	No	No

As nouns, weed puller is a hyponym of weeder; that is, weed puller is a word with a more specific, narrower meaning than weeder:

weeder: a hand tool for removing weeds
weed puller: a weeder with steel claws that grab weeds by the root for clean removal.

Other hyponyms of weeder include weed remover.

weeder (noun)	weed puller (noun)
a hand tool for removing weeds	a weeder with steel claws that grab weeds by the root for clean removal.
a farmhand hired to remove weeds