As an adjective: straight, level, direct. As an adverb (the most common NT usage): immediately, at once, without delay. Mark uses euthus frequently as his characteristic narrative word.
Mark's Gospel uses euthus (translated 'straightway' or 'immediately') over 40 times, making it his narrative signature. Jesus calls disciples β and euthus they follow. He commands a demon β and euthus it departs. He heals β and euthus the person is whole. This rapid-fire pace conveys the explosive, unstoppable power of the Kingdom of God breaking into history. Nothing can delay or detour the purposes of Christ. In its adjective form, euthus describes the straight path β God calls His people to walk euthus ways, undeviated by compromise or fear.