dun·der·head 
(dŭndər-hĕd′)
(dŭndər-hĕd′)n.
A dunce.
[Perhaps Dutch donder, thunder (from Middle Dutch doner; see (s)tenə- in the Appendix of Indo-European roots) + HEAD.]
dunder·head′ed adj.
- conspirational
- conspirator
- conspiratorial
- conspiratorialist
- conspiratorially
- conspire
- conspirer
- conspiringly
- con spirito
- constable
- Constable
- constableship
- constabular
- constabulary
- Constance
- Constance
- Constance
- Constance Black
- constancy
- constant
- constantan
- Constant de Rebecque
- constant dollars
- Constantin
- Constantine