justly

adverb3

1. •
   In a just or fair manner; rightfully.

   • His valor, wisdom, and justice made him justly popular, but caused him to be regarded with suspicion at Rome. — 1890
2. •
   With a just or fair use of language; with good reason, properly.

   • But the city on the River Clyde can justly claim to have turned the tide. — 2012
3. •
   (no longer used) With great precision; accurately, exactly.

   • It is a pleasant imagination to conceive a spirit iustly ballanced betweene two equall desires. — 1603