In the following question, choose the one-word substitute for the given expression: a person who loads and unloads ships at a port or dock.

Introduction / Context:
In competitive English examinations, one-word substitution questions are very common. They test whether the learner knows an exact technical or occupational term for a longer descriptive phrase. Here the phrase describes a person whose regular job is loading and unloading cargo from ships at a dock or port. The goal is to identify the precise noun used in standard English for this occupation.

Given Data / Assumptions:
- The phrase to be converted into a single word is “one who loads and unloads ships at a port or dock”.
- Five alternative words are given: Stevedore, Transgressor, Lapidist, Reticent, Longshoreman.
- Only one of these correctly and exactly names that profession.

Concept / Approach:
The key approach in one-word substitution questions is vocabulary knowledge. We must know or deduce the meanings of all the options, then match the definition in the stem with the most accurate term. It is important not to be misled by words that look sophisticated but have unrelated meanings. Occupational vocabulary, especially for older trades like shipping, often has very specific words that students are expected to remember for exams.

Step-by-Step Solution:
Step 1: Focus on the central idea: the person works with ships and handles cargo being loaded and unloaded. Step 2: Recall that in English, the traditional word for such a dock worker who loads or unloads cargo is “stevedore”. This term is widely used in shipping contexts. Step 3: Check option A: “Stevedore” – this indeed means a labourer responsible for loading and unloading cargo from a ship. Step 4: Check option B: “Transgressor” – this refers to someone who breaks a rule or law, not a port worker. Step 5: Check option C: “Lapidist” – this is a person who cuts, polishes or engraves precious stones, a completely different profession. Step 6: Check option D: “Reticent” – this is an adjective meaning reserved or not talkative, not an occupational noun. Step 7: Check option E: “Longshoreman” – this is also a dock worker, but the phrase in the question is more traditionally associated with the technical term “stevedore”, which exam patterns usually expect. Step 8: Conclude that “Stevedore” is the best and most precise one-word substitute for the given phrase.

Verification / Alternative check:
Dictionaries define “stevedore” as a labourer who loads and unloads cargo from ships in a port. Some regions also use the term “longshoreman”, and in everyday language both may be heard. However, classical one-word substitution questions in standard exam books consistently list “stevedore” as the expected answer for this particular phrase. This confirms that choosing option A aligns with both dictionary usage and exam convention.

Why Other Options Are Wrong:
- Transgressor: describes a wrongdoer or lawbreaker, totally unrelated to ships or ports.
- Lapidist: refers to a person working with precious stones, not with cargo on ships.
- Reticent: an adjective about character (being quiet), not a job title.
- Longshoreman: related to dock work but less standard in traditional exam keys for this exact phrase; “stevedore” is more precise in this context.

Common Pitfalls:
Learners sometimes pick a word simply because it sounds advanced, without knowing its meaning. Another pitfall is confusion between similar occupations, such as sailors, captains, porters, and dock workers. Remember that “stevedore” is closely tied to the work of loading and unloading ships, not sailing them or policing the port. Carefully matching each option to the phrase prevents such errors.

Final Answer:
The correct one-word substitute for “one who loads and unloads ships at a port or dock” is Stevedore.