予防線 よぼうせん Meanings Noun defensive perimeter; defence line; defense line; defensive measures precaution; safeguard; safety measure (usu. as 予防線を張る) See also: 予防線を張る (よぼうせんをはる). Kanji 予 pre-. Read as ヨ. 防 defend. Read as ボウ. 線 line. Read as セン. Words containing 予防線 予防線を張る (よぼうせんをはる) to take precautions Jinuma: Japanese Dictionary · Word lists