We don't have synonyms for undercard yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are undergird, underhand and underarm.
(n) :
A list of minor or supporting contests printed on the same bill as the main event (primarily fighting or racing, such as the main fight at a boxing match or wrestling, horse or car racing, etc.), occurring before or after the main event.
(n) :
The events so listed.
(n) :
(politics) The supporting candidate on a ticket, such as vice president.
(n) :
(poker) A card lower than another given card or pair.
(n) :
A list of minor or supporting contests printed on the same bill as the main event (primarily fighting or racing, such as the main fight at a boxing match or wrestling, horse or car racing, etc.), occurring before or after the main event.
(n) :
The events so listed.
(n) :
(politics) The supporting candidate on a ticket, such as vice president.
(n) :
(poker) A card lower than another given card or pair.