question, problem

(gate) Same-ON + (mouth/small box radical)
★★★★★
11 strokes

Onyomi

MON

Mnemonic

The MONK, standing at the temple gate, asks you a question : (a Zen koan) with his mouth. If you answer wrong, you can't get in.

Kunyomi

と*う to ask (BOOBOO: only used in a formal situation, where the wrong answer spells trouble: - the police questioned the suspect, the situation calls his authority into question) F
★★☆☆☆

Jukugo

質問(しつもん) する

question ★★★★★
(quality) + (question, problem) = 質問 (question)

a question - usually used in a structured setting: interview, trial, test. 

BOOBOO: in casual conversation, people will say 尋ねる or 聞く instead of 質問.

問題(もんだい)

problem ★★★★★
(question, problem) + (topic) = 問題 (problem)

problem - as in "environmental pollution", also as in "homework problem"

疑問(ぎもん)

a doubt  ★★★☆☆
(doubt) + (question, problem) = 疑問 (a doubt )

a doubt (疑問がある= I have doubts about it.)

Lookalikes

Meaning Hint Radical
gate OPEN
a period of time DAY
question, problem MOUTH

Gate has NOTHING IN THE CENTER, IT'S OPEN - so you can walk through it.

There is an interval of one DAY between things, and you ask a question with your MOUTH.

Synonyms

ask question
に聞く    に尋ねる    に問う    に質問する    に伺う   
visit
へ伺う    に参る    を訪ねる    を訪問