| strict(adjective, severe, firm, harsh, stiff) |
| tough(adjective, severe, firm, harsh, rigid) |
| uncompromising(adjective, cruel, pitiless, heartless, hardhearted) |
| unrelenting(adjective, mean, severe, harsh, cruel) |
| unsympathetic(adjective, mean, severe, harsh, cruel) |
| acrimonious(adjective, severe, harsh, stiff, rigid) |
| austere(adjective, tough, severe, firm, harsh) |
| authoritarian(adjective, tough, severe, firm, harsh) |
| barbarous(adjective, mean, severe, harsh, cruel) |
| binding(adjective, severe, harsh, stiff, rigid) |
| bound(adjective, persistent, constant, pitiless, unyielding) |
| bound and determined(expression, adjective, idiom, persistent, constant) |
| brick-wall(adjective, severe, stiff, rigid, tight) |
| by the book(expression, adjective, idiom, severe, harsh) |
| by the numbers(expression, adjective, idiom, severe, harsh) |
| callous(adjective, mean, severe, harsh, cruel) |
| ceaseless(adjective, persistent, constant, pitiless, unyielding) |
| cold-blooded(adjective, cruel, pitiless, heartless, hardhearted) |
| cold-fisted |
| compassionless(adjective, mean, severe, harsh, cruel) |