If a player does not follow suit when able (usually by playing a trump card instead), it is considered a renege (or revoke), and the opposing team is awarded two points if it is caught in later tricks of the same hand or two points can be deducted from the offending team.

In trick-taking card games, a revoke (or renege, /rɪˈneɪɡ/ or /rɪˈniːɡ/) is a violation of the rules regarding the play of tricks serious enough to render the round invalid. … Spades, Euchre and 500 require that players play to the suit led, unless void in it. Hearts requires that players follow the suit led.