|
hardest : 2463 phrases in 206 subjects |
| Accounting | 2 |
| Advertising | 25 |
| Agriculture | 11 |
| Agrochemistry | 6 |
| Alternative dispute resolution | 2 |
| American usage, not spelling | 24 |
| Animal husbandry | 3 |
| Antennas and waveguides | 1 |
| Apollo-Soyuz | 1 |
| Architecture | 5 |
| Armored vehicles | 14 |
| Art | 1 |
| Artificial intelligence | 1 |
| Artillery | 2 |
| Astrology | 1 |
| Astronautics | 31 |
| Astronomy | 2 |
| Audit | 1 |
| Australian | 8 |
| Automated equipment | 46 |
| Automobiles | 18 |
| Aviation | 15 |
| Aviation medicine | 1 |
| Ballistics | 1 |
| Banking | 3 |
| Biology | 8 |
| Bookish / literary | 2 |
| Botany | 12 |
| Boxing | 4 |
| Bridge construction | 1 |
| British usage, not spelling | 1 |
| Building materials | 1 |
| Business | 4 |
| Cartography | 2 |
| Caspian | 2 |
| Cement | 5 |
| Chemical industry | 2 |
| Chemistry | 9 |
| Chess | 2 |
| Cinematography | 2 |
| Cliche / convention | 5 |
| Coal | 1 |
| Commerce | 2 |
| Communications | 2 |
| Computer games | 2 |
| Computer networks | 1 |
| Computers | 17 |
| Computing slang | 1 |
| Confectionery | 1 |
| Construction | 40 |
| Contextual meaning | 1 |
| Cooking | 6 |
| Criminal law | 1 |
| Dentistry | 7 |
| Dialectal | 1 |
| Digital currencies, cryptocurrencies, blockchain | 1 |
| Diplomacy | 12 |
| Drilling | 4 |
| Drug-related slang | 2 |
| Ecology | 4 |
| Economics | 14 |
| Education | 2 |
| Electrical engineering | 3 |
| Electrochemistry | 2 |
| Electronics | 50 |
| Energy industry | 1 |
| Engines | 1 |
| European Bank for Reconstruction and Development | 5 |
| Figurative | 23 |
| Figure of speech | 4 |
| Finances | 10 |
| Firefighting and fire-control systems | 1 |
| Fish farming pisciculture | 12 |
| Food industry | 8 |
| Football | 4 |
| Footwear | 1 |
| Forestry | 13 |
| Gastroenterology | 2 |
| General | 755 |
| Geology | 17 |
| Geophysics | 2 |
| Gold mining | 3 |
| Grammar | 1 |
| Historical | 1 |
| Hovercraft | 1 |
| Human resources | 4 |
| Humorous / Jocular | 1 |
| Hydrobiology | 1 |
| Hydrology | 5 |
| Ichthyology | 3 |
| Idiomatic | 11 |
| Informal | 61 |
| Information security and data protection | 9 |
| Information technology | 44 |
| Insurance | 3 |
| International Monetary Fund | 1 |
| Internet | 1 |
| Investment | 1 |
| Kayaking | 1 |
| Labor law | 1 |
| Law | 11 |
| Leather | 5 |
| Librarianship | 2 |
| Linguistics | 4 |
| Literature | 2 |
| Logging | 1 |
| Logistics | 1 |
| Makarov | 125 |
| Management | 1 |
| Mass media | 24 |
| Materials science | 1 |
| Mathematics | 2 |
| Mechanic engineering | 14 |
| Mechanics | 2 |
| Medical | 25 |
| Metal science | 2 |
| Metallurgy | 25 |
| Meteorology | 2 |
| Metrology | 1 |
| Microelectronics | 5 |
| Microsoft | 7 |
| Military | 61 |
| Military aviation | 1 |
| Military lingo | 2 |
| Mineral processing | 1 |
| Mineral products | 2 |
| Mining | 11 |
| Missiles | 5 |
| Music | 2 |
| Name of organization | 2 |
| Nanotechnology | 18 |
| Natural resourses and wildlife conservation | 1 |
| Nautical | 49 |
| Navigation | 2 |
| New Zealand | 1 |
| Non-destructive testing | 13 |
| Non-governmental organizations | 2 |
| Notarial practice | 1 |
| Nuclear and fusion power | 3 |
| Obsolete / dated | 6 |
| Oil / petroleum | 23 |
| Oil and gas | 20 |
| Oil and gas technology | 4 |
| Oil processing plants | 1 |
| Oilfields | 4 |
| Ornithology | 1 |
| Orthopedics | 2 |
| Packaging | 3 |
| Painting | 1 |
| Patents | 1 |
| Perfume | 4 |
| Pharmacology | 1 |
| Pharmacy and pharmacology | 1 |
| Phonetics | 1 |
| Photography | 1 |
| Physical chemistry | 2 |
| Physics | 8 |
| Politics | 21 |
| Polygraphy | 16 |
| Polymers | 14 |
| Prison slang | 1 |
| Production | 2 |
| Programming | 40 |
| Proverb | 12 |
| Psychology | 8 |
| Pulp and paper industry | 4 |
| Pumps | 1 |
| Quality control and standards | 3 |
| Quantum electronics | 1 |
| Rail transport | 12 |
| Refrigeration | 1 |
| Religion | 1 |
| Rhetoric | 3 |
| Road works | 2 |
| Robotics | 1 |
| Roll stock | 2 |
| Rude | 1 |
| Sakhalin | 6 |
| Saying | 2 |
| Scientific | 1 |
| Security systems | 8 |
| Shipbuilding | 3 |
| Silicate industry | 3 |
| Skiing | 1 |
| Slang | 56 |
| Software | 3 |
| Soil science | 1 |
| Soviet | 1 |
| Sports | 10 |
| Survey | 1 |
| Table tennis | 3 |
| Technology | 136 |
| Telecommunications | 9 |
| Textile industry | 17 |
| Thermal engineering | 1 |
| Tobacco industry | 1 |
| Transport | 12 |
| Uncommon / rare | 4 |
| Veterinary medicine | 1 |
| Vulgar | 19 |
| Water resources | 4 |
| Weapons and gunsmithing | 5 |
| Welding | 4 |
| Wood processing | 4 |
| Yachting | 1 |
| Zoology | 1 |