Secondly (adverb)
In the second place.
Secondarily (adverb)
With lesser importance.
“Primarily, this will cause deaths; secondarily, it will also cost a lot of money.”
Secondarily (adverb)
In a secondary manner or degree.
Secondarily (adverb)
Secondly; in the second place.
Wiktionary
Secondly (adverb)
in the second place (used to introduce a second point or reason)
“he was presented first of all as a hopelessly unqualified candidate and secondly as an extremist”
Oxford Dictionary