/un'euh kown"tid fawr'/, adj.
not accounted for; not understood; unexplained: an explosion resulting from some unaccounted-for mechanical failure.
[1790-1800; formed on the v. phrase account for; see UN-1, -ED2]
* * *
unaccountˈed-for adjective
1. Unexplained
2. Missing without explanation
3. Not included in an account
Useful english dictionary. 2012.