brutal, frenzied, horrific, savage, serious, vicious, violent
unprovoked
Stephen had died in an unprovoked racist attack.

homophobic, racist
arson, gun, knife
an increase in knife attacks on police officers

sexual

series, spate, wave

carry out
Two teenagers carried out a frenzied attack on a taxi driver.

be subjected to
He was subjected to a violent attack.

block, dodge

happen, occur, take place
Where did the attack happen?

attack against
vicious attacks against senior citizens

attack by
an attack by an armed gang

attack on
an attack on a bus driver

a victim of an attack

all-out, full-scale, major
sustained
deadly, devastating
horrific
sneak, surprise
the sneak attack on Pearl Harbor

retaliatory
pre-emptive
The administration may launch a pre-emptive attack against terrorist bases.

mock
direct, flank, frontal
enemy, guerrilla, insurgent, terror, terrorist
suicide
air, bomb, missile, mortar, nuclear, rocket
biological, chemical

series
The border towns have suffered a series of attacks.

carry out, launch, lead, make, mount, spearhead
The soldiers mounted an all-out attack on the town.

come under, suffer
They came under sustained attack from the air.

repel, repulse, resist
prevent, stop
survive, withstand
Most of the population would stand little chance of surviving a nuclear attack.

press (esp. AmE), press home (esp. BrE), renew
Bombers renewed their attack, causing severe damage to bridges.

plan

come, happen, occur, take place
The attack took place under cover of darkness.

continue
fail, succeed

under attack
The province has been under attack from the rebels.

attack against
attacks against civilians

attack by
an attack by rebel forces

attack on
an attack on enemy positions

bitter, blistering, devastating, fierce, outspoken (BrE), savage, scathing, scurrilous, stinging, vigorous
personal
It was seen as a personal attack on the president.

concerted
direct
verbal

deliver, go on the, launch, make, mount, unleash
Doctors have gone on the attack, accusing the government of incompetence.

come under, provoke
All politicians come under attack for their views.
The government's decision has provoked an attack from leaders of the health service.

attack on, attack upon
an attack on my integrity

a/the line of attack
The first line of attack is often name-calling.

open to attack
He has laid himself wide open to attack.

acute, sudden
bad, nasty, severe
fatal
mild, slight
recurrent
asthma, heart, panic
a fatal heart attack

experience, have, suffer, suffer from
He suffers from attacks of anxiety.

bring on, cause, trigger
a heart attack brought on by stress

happen, occur, take place

attack of
a sudden attack of nerves

brutally, savagely, viciously, violently
They were brutally attacked by two men.

physically
repeatedly

with
He attacked her with a knife.

fiercely, savagely, strongly, vigorously
repeatedly
directly

for
The police have been strongly attacked for not taking immediate action.

Attack is used with these nouns as the subject:
aircraft, army, article, critic, demonstrator, dog, enemy, fanatic, lion, mob, monster, rapist, rebel, report, shark, tank, troops, vandal, virus

Attack is used with these nouns as the object:
bacteria, barracks, base, camp, castle, cell, civilian, convoy, corruption, country, embassy, enemy, flank, fort, fortress, neighbour, opponent, patrol, problem, rebel, ship, target, vessel