fathom

fathom — verb

  • fathompresent simple I / you / we / they
  • fathomshe / she / it
  • fathomedpast simple
  • fathoming-ing form

1. to understand a difficult idea, reason, or situation after thinking about it

1.動詞及物C1
釋義

to understand a difficult idea, reason, or situation after thinking about it

例句

Constanza could not fathom why the shop closed on market day.

cannot fathom + why-clause for puzzling situations

After two lectures, Gabriel finally fathomed the diagram of the engine.

同義詞
  • understand

    broader and more neutral; 'fathom' suggests difficulty

  • grasp

    often used for clearly seeing an idea once it clicks

  • figure out

    more informal and problem-solving in tone

文法句型

fathom + noun phrase (a reason, an idea, a decision)

cannot/could not fathom + wh-clause

用法筆記

Most often used for ideas, reasons, or situations that seem hard to explain, and it appears especially often with cannot or could not. Distinguish from sense 2 (READ SOMEONE): this sense is about problems or explanations, not a person's feelings.

常見錯誤

❌I can't fathom about his decision.
✅I can't fathom his decision.
💡use a direct object after 'fathom', not 'about'.
❌She fathomed to answer the puzzle.
✅She fathomed the answer to the puzzle.
💡'fathom' takes the thing understood as its object.

2. to understand a person's feelings, motives, or behaviour

2.動詞及物C2
釋義

to understand a person's feelings, motives, or behaviour

例句

Nila could never fathom why her brother stayed silent during arguments.

fathom + why-clause about a person's behaviour

Walid spent years trying to fathom his father's fear of flying.

同義詞
  • read

    more informal; often used for noticing someone's feelings quickly

  • understand

    broader and less focused on hidden motives

  • figure out

    emphasizes working out why someone acts that way

文法句型

fathom + person

fathom + someone's feelings/reaction

fathom + why + clause

用法筆記

Use this sense when the object is a person or that person's motives, not an abstract problem. It often appears with why or what when the speaker is trying to explain someone's behaviour.

常見錯誤

❌I can't fathom with my manager.
✅I can't fathom my manager.
💡use a direct object, not 'with'.
❌I can't fathom him why he left.
✅I can't fathom why he left.' or ✅ 'I can't fathom him.
💡do not combine both patterns in one clause.

3. to measure how deep water is by lowering a line or another sounding tool

3.動詞及物C2
釋義

to measure how deep water is by lowering a line or another sounding tool

例句

Before dawn, the crew fathomed the harbor before guiding the ferry in.

nautical use: fathom + harbor before entering

Sailors stopped to fathom the channel when the fog grew thicker.

同義詞
  • sound

    the closest nautical verb; especially used by sailors

  • measure

    broader and more modern than 'fathom'

文法句型

fathom + harbor/channel/river/bay

fathom + body of water + with + line

用法筆記

This is an old or technical sense linked to ships and waterways. In modern general English, people usually say measure the depth of instead.

常見錯誤

❌The team fathomed the cave wall.
✅The team measured the cave wall.
💡this sense is for checking water depth, not ordinary measurement.
❌They fathomed the road with a ruler.
✅They measured the road with a ruler.
💡'fathom' is tied to sounding water, not flat surfaces.

fathom — noun