The old man played cards to pass the boring day.

Literal

Old-man [topic-は] cards [with-で] boring one-day [object-を] distracted.

まぎらす ('to divert, distract') combined with 退屈 means 'to relieve boredom.' トランプ refers to playing cards in Japanese — not the English word 'trump.' This is a common wasei-usage that surprises English speakers.