倦 is rarely used alone in modern Chinese; it typically appears in compounds: 疲倦 (fatigued), 厌倦 (weary of/bored with), 倦怠 (exhaustion/burnout). 厌倦 implies mental weariness, while 疲倦 is more physical.
Standing-person radical on the left - the side-form of 人. Indexes 倦 in the human-state family with 休 rest, 体 body, 健 healthy. Marks the character as a condition of a person: here, the worn-out feeling that comes from prolonged effort.
Right side 卷 supplies the sound with a tone shift: juǎn to juàn. It also adds a faint semantic image - a person curled up like a rolled-up scroll, hunched from fatigue. Same phonetic appears in 圈 circle, all carrying the curl-up flavour.
