ଅର୍ଥ : In a way that was not expected.
ଉଦାହରଣ :
Her brother showed up at the wedding out of the blue.
ସମକକ୍ଷ : out of the blue
ଅର୍ଥ : Without advance planning.
ଉଦାହରଣ :
They met accidentally.
ସମକକ୍ଷ : accidentally, by chance, circumstantially
With intention. In an intentional manner.
He used that word intentionally.