Translation guide
To play a stringed instrument by sweeping the fingers or a pick across the strings, often casually or rhythmically.
strum a guitar
To casually sweep the fingers or a pick across the strings of a guitar, ukulele, or similar instrument, often without a specific melody.
General verb for playing a stringed instrument. Can be used for strumming, but also for plucking or playing in general. Context makes it clear.
strum a guitar
He was sitting on the sofa strumming his guitar.
To strum vigorously or roughly, often with energy. Implies a more forceful, rhythmic strumming.
strum a guitar loudly/energetically
Literally 'play with strokes'. Used in musical contexts to specify strumming as opposed to fingerpicking.
This song sounds good when strummed.
To strum in a particular rhythmic pattern, often as part of learning or performing a song.
To strum lightly and without purpose, often while thinking or relaxing.
The direct loanword ストラム is not commonly used in Japanese. Use 弾く or ストローク instead.
I was just strumming the guitar randomly and came up with a nice tune.