[YouServ]

I give you 3 methods :

PHP Code:

/*
    FIRST METHOD :
*/
new
    timer_Waiting[MAX_PLAYERS];
    
CMD:wait(playerid, params[])
{
    if(timer_Waiting[playerid] > 0)
        return SendClientMessage(playerid, -1, "You can't use this command now.");
        
    // Script of your commands
    timer_Waiting[playerid] = 5; // Wait 5 seconds after retype this command.
    SetTimerEx("WaitingCommands", 1000, false, "i", playerid); // Dйsincrement the variable all seconds of 1 value.
}
forward WaitingCommands(playerid);
public WaitingCommands(playerid)
{
    timer_Waiting[playerid]--;
    return 1;
} 


PHP Code:

/*
    SECOND METHOD :
*/
new
    bool:blockedCmds[MAX_PLAYERS];
CMD:wait(playerid, params[])
{
    if(blockedCmds[playerid] == true)
        return SendClientMessage(playerid, -1, "You can't use this command now.");
    // Script of your commands
    blockedCmds[playerid] = true; // Turn the boolean variable to "true".
    SetTimerEx("WaitingCommands", 5000, false, "i", playerid); // In 5 seconds, we turn the boolean variable to "false"
}
forward WaitingCommands(playerid);
public WaitingCommands(playerid)
{
    timer_Waiting[playerid] = false;
    return 1;
} 


PHP Code:

/*
    THIRTY METHOD :
*/
new
    timer_Waiting[MAX_PLAYERS];
CMD:wait(playerid, params[])
{
    if(timer_Waiting[playerid] < gettime()+5000)
        return SendClientMessage(playerid, -1, "You can't use this command now.");
    // Script of your commands
    timer_Waiting[playerid] = gettime(); // Save the actual time and check if "5s" was ecouled
}