As a noun sparkplug is
.
ignitionplug
Not English
Ignitionplug has no English definition. It may be misspelled. sparkplug
English
Noun
(
en noun)
* {{quote-news, year=2009, date=May 30, author=Al Baker, title=Investigators Reviewing a Timeline of Seconds That Led to a Police Shooting, work=New York Times citation
, passage=Mr. Santiago used a
sparkplug to smash the driver’s side window. }}