Synonyms for In the first place:

adv.

all (adverb)
originally, to begin with, earlier, in the beginning, primarily.
chiefly (adverb)
primarily.
first (adverb)
to begin with, originally.
originally (adverb)
in the beginning.

adv

initially (adverb)
originally.
in the beginning (adverb)
primarily.
originally (adverb)
in the beginning.

n.

in the first place (noun)
originally, to begin with, earlier, in the beginning, primarily.

Other synonyms:

adv
to begin with.
n.
to begin with.
Other relevant words:
in the beginning.