Dictionary.com
Thesaurus.com
Synonyms

rightly

American  
[rahyt-lee] / ˈraɪt li /

adverb

  1. in accordance with truth or fact; correctly.

    to see rightly; to understand rightly.

  2. in accordance with morality or equity; uprightly.

  3. properly, fitly, or suitably.

    to be rightly dressed.

  4. Informal. with certainty; positively.

    I can't rightly say.


rightly British  
/ ˈraɪtlɪ /

adverb

  1. in accordance with the facts; correctly

  2. in accordance with principles of justice or morality

  3. with good reason; justifiably

    he was rightly annoyed with her

  4. properly or suitably; appropriately

    rightly dressed for a wedding

  5. informal (used with a negative) with certainty; positively or precisely (usually in the phrases I don't rightly know, I can't rightly say )

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of rightly

before 900; Middle English; Old English rihtlīce. See right, -ly