dilakukan tanpa persiapan bahasa Inggris

• extemporaneous
• improvised
• extemporal
• unscheduled
• off-the-cuff
• extemporary
• autoschediastic
• impromptu

• dilakukan:    play at
• tanpa:    bare of; devoid of; freshed out of; freshing out
• tanpa persiapan:    extempore; halfcocked; offhand; at short notice;
• persiapan:    arrangement; on the fire; preliminary;

Contoh

1. This wasn't the random act of some mindless horde.
   Ini bukanlah serangan acak yang dilakukan tanpa persiapan.