These are the updated answers to Knight levels 1 to 20 with step by step video walkthrough. If you need help with next difficult level Tiger, check it out.
Level 1 – priority, prince, unlikely, notice, festival, conflict, lifetime, specifically
Level 2 – effort, opponent, doctor, slight, suppose, battery, instance, burden, depression
Level 3 – system, historic, complain, through, between, witness, climate, retire, purchase
Level 4 – familiar, drawing, apparent, silent, likely, creature, number, limited, somebody
Level 5 – thanks, criminal, identify, channel, duration, compass, uniform, appoint, ground
Level 6 – nowhere, favorite, reader, tragedy, accurate, normally, intend, guilty, headline
Level 7 – musical, complete, supreme, typical, painting, property, gently, directly, ratio
Level 8 – anyway, quietly, pepper, within, division, mineral, protein, account, absolutely
Level 9 – nearby, athletic, probably, oppose, chicken, plastic, printer, module, community
Level 10 – struggle, monster, carrier, fitness, concern, perfect, artist, better, democracy
Level 11 – wealthy, profit, ladder, density, widely, business, auction, lawsuit, particular
Level 12 – worker, sandwich, breach, discover, circle, inform, imagine, Indian, destruction
Level 13 – strongly, resemble, justice, adequate, kitchen, vendor, object, software, crisis
Level 14 – prisoner, numerous, mystery, injury, needle, equally, adjust, funnel, comparison
Level 15 – infinity, vampire, relative, official, fragment, builder, cereal, professional
Level 16 – hungry, bullet, accident, element, chamber, thousand, abroad, butter, definition
Level 17 – veteran, reform, civilian, credit, mountain, amount, explain, regulate, unicycle
Level 18 – umbrella, persuade, inquiry, position, viewer, effect, weekly, visitor, receiver
Level 19 – willing, interest, faculty, throat, coverage, rhythm, shower, support, effective
Level 20 – stranger, ethnic, modest, decline, dividend, qualify, travel, buckle, aggressive

The solutions to the puzzles were last updated on April 27, 2019