| straight(adjective, adverb, direct, smooth, right) |
| upright(adjective, smooth, solid, level, true) |
| perpendicular(adjective, smooth, solid, short, straight) |
| vertical(adjective, smooth, solid, level, true) |
| fathom(verb, sound, grasp, understand, divine) |
| erect(adjective, smooth, solid, level, true) |
| sound(noun, verb, check, mark, determine) |
| measure(noun, verb, determine, sound, grasp) |
| even(adjective, adverb, check, mark, determine) |
| gauge(noun, verb, check, mark, determine) |
| plummet(noun, verb, drop, fall, lead) |
| squarely(adverb, just, absolutely, exactly, directly) |
| exactly(adverb, just, absolutely, completely, directly) |
| plumb bob(noun, expression, idiom, lead, line) |
| right(adjective, adverb, direct, smooth, flat) |
| absolutely(adverb, just, fully, completely, exactly) |
| clean |
| penetrate(verb, grasp, understand, divine, comprehend) |
| probe(verb, grasp, understand, divine, comprehend) |
| sheer(adjective, smooth, solid, level, true) |