i Register
In some senses, haply is marked as archaic, literary. Watch for register when choosing this word.
adv
By accident or luck.
But as soon as her son espied her, bowl in hand, he thought that haply something untoward had befallen her, but he would not ask of aught until such time as she had set down the bowl, when she acquainted him with that which had occurred[…]
Perhaps; by chance.
"O my lord the Sultan," said the other [the Wazir], "verily women be weakly of wits, and haply this goodwife cometh hither to complain before thee against her goodman or some of her people."
"Ha," quoth he to himself, "I will go and inquire into this business, for it may haply be that yonder black knight shall not find it to be so easy to deal with a knight of the Round Table as with those other three knights."