| plodding(adjective, hard, difficult, complex) |
| serious(adjective, hard, difficult, harsh, cruel) |
| sticky(adjective, hard, difficult, complex, awkward) |
| thorny(adjective, hard, difficult, complex) |
| tight(adjective, hard, difficult, complex) |
| toilful(adjective, hard, difficult, complex, awkward) |
| tough(adjective, hard, difficult, complex) |
| weighty(adjective, hard, difficult, complex) |
| hard-nosed(adjective, hard, difficult, complex, severity) |
| intricate(adjective, hard, difficult, complex, awkward) |
| operose(adjective, hard, difficult, complex, awkward) |
| sore(adjective, hard, difficult, pain, complex) |
| rasping(noun, verb, adjective, rough, clean) |
| grating(noun, verb, adjective, rough, harsh) |
| abrasion(noun, clean, stroke, contact, resistance) |
| attrition(noun, clean, stroke, contact, resistance) |
| scraping(noun, verb, adjective, clean, stroke) |
| crushing(noun, adjective, severe, harsh, heavy) |
| wearing(noun, verb, adjective, tough, rough) |
| chafing(noun, verb, adjective, contact, friction) |