18 Heb “Kerethites,” a people settled alongside the Philistines in the coastal areas of southern Palestine (cf. 1 Sam 30:14; Ezek 25:16). They originally came from the island of Crete.
19 Heb “Woe, inhabitants of the coast of the sea, nation of Kerethites.” The Hebrew term הוֹי (hoy, “ah, woe”), is used to mourn the dead and express outwardly one’s sorrow (see 1 Kgs 13:30; Jer 22:18; 34:5). By using it here the prophet mourns in advance the downfall of the Philistines, thereby emphasizing the certainty of their demise (“as good as dead”). Some argue the word does not have its earlier connotation here and is simply an attention-getting interjection, equivalent to “Hey!”
20 Heb “the word of the Lord is against you.”
21 Heb “I will destroy you so there is no inhabitant [remaining].”

In other versions

Woe to you inhabitants of the seacoast,

you nation of the Cherethites!

The word of the Lord is against you,

O Canaan, land of the Philistines;

and I will destroy you until no inhabitant is left.

Woe to you who live by the sea,

you Kerethite people;

the word of the Lord is against you,

Canaan, land of the Philistines.

He says, “I will destroy you,

and none will be left.”

Woe, inhabitants of the seacoast,

nation of the Cherethites!

The word of the Lord is against you,

Canaan, land of the Philistines:

I will destroy you until there is no one left.

And what sorrow awaits you Philistines

who live along the coast and in the land of Canaan,

for this judgment is against you, too!

The Lord will destroy you

until not one of you is left.

Woe to you, inhabitants of the region of the sea,

people of the Kerethites!

The word of Yahweh is against you,

O Canaan, land of the Philistines.

I will destroy you until there is no inhabitant.

Woe unto the inhabitants of the sea coast, the nation of the Cherethites!

The word of the Lord is against you;

O Canaan, the land of the Philistines,

I will even destroy thee, that there shall be no inhabitant.

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