o·ver·hear 
(ō′vər-hîr)
(ō′vər-hîr)v. o·ver·heard (-hûrd), o·ver·hear·ing, o·ver·hears
v.tr.
To hear (speech or someone speaking) without the speaker's awareness or intent.
v.intr.
To hear something without the speaker's awareness or intent.
o′ver·hearer n.