What did haply mean in shakespearean language?

Random House Webster's College Dictionary

1. (adv.) haply

perhaps; by chance.

Definition of 'haply' Princeton's WordNet

1. (adverb) haply, by chance, by luck

by accident

"betrayed by a word haply overheard"

Definition of 'haply' Webster Dictionary

1. (adverb) haply

by hap, chance, luck, or accident; perhaps; it may be