noun
all-out attack; attack on all fronts; onslaught
A coordinated, simultaneous attack from multiple directions or by all available forces. Often used in military, sports, or figurative contexts.
敵は夜明け前に一斉攻撃を仕掛けてきた。
The enemy launched an all-out attack before dawn.
野党は首相の政策に対して一斉攻撃を始めた。
The opposition parties began a coordinated attack on the prime minister's policies.
総攻撃 also means a general or all-out attack, but 一斉攻撃 emphasizes simultaneity and coordination, while 総攻撃 can imply a full-scale offensive without the same focus on timing.
Compound of 一斉 (simultaneous) and 攻撃 (attack).