From the NannyMUD documentation

LAST CHANGE

2000-12-16

TOPIC

NAME

        keywords - Reserved words.

DESCRIPTION

        The following identifiers are reserved for use as keywords, and may
        not be used for any other purpose:

        _acl_access
        _acl_debug
        _acl_get
        _acl_modify
        _acl_num2str
        _acl_put
        _acl_query_access
        _acl_str2num
        _cache_stats
        _chmod
        _destruct
        _disconnect
        _driver_stat
        _dump_file_descriptors
        _file_stat
        _find_shortest_path
        _fuzzymatch
        _get_clone_by_number
        _get_spec_obj
        _isclone
        _lock
        _m_delete
        _next_clone
        _object_cpu
        _object_memory
        _object_stat
        _query_action
        _query_ed
        _rusage
        _set_prompt
        _syslog
        _wiz_list_info
        add_action
        add_verb
        add_worth
        add_xverb
        all_inventory
        allocate
        assoc
        atoi
        break
        break_point
        call_other
        call_out
        call_out_info
        capitalize
        case
        cat
        catch
        clear_bit
        clone_object
        command
        continue
        create_wizard
        creator
        crypt
        ctime
        debug_info
        deep_inventory
        default
        destruct
        disable_commands
        do
        dump_socket_status
        ed
        else
        enable_commands
        environment
        exec
        explode
        extract
        file_name
        file_size
        filter_array
        filter_mapping
        find_call_out
        find_living
        find_object
        find_player
        first_inventory
        float
        for
        foreach
        function_exists
        get_dir
        glob
        if
        implode
        inherit
        inherit_list
        input_to
        insert_alist
        int
        interactive
        intersect_alist
        intp
        living
        localcmd
        log_file
        lower_case
        m_delete
        m_indices
        m_sizeof
        m_values
        map_array
        map_mapping
        mapping
        mappingp
        member_array
        mixed
        mkdir
        mkmapping
        move_object
        next_inventory
        next_living
        nomask
        notify_fail
        object
        objectp
        order_alist
        parse_command
        pointerp
        present
        previous_object
        private
        process_string
        protected
        public
        query_host_name
        query_idle
        query_ip_number
        query_ip_port
        query_load_average
        query_snoop
        query_verb
        random
        read_bytes
        read_file
        regexp
        remove_call_out
        rename
        replace
        restore_object
        return
        rm
        rmdir
        save_object
        say
        set_bit
        set_heart_beat
        set_light
        set_living_name
        shadow
        shared
        shout
        shutdown
        sizeof
        snoop
        socket_accept
        socket_acquire
        socket_address
        socket_bind
        socket_close
        socket_connect
        socket_create
        socket_error
        socket_listen
        socket_release
        socket_write
        sort_array
        sprintf
        sscanf
        static
        status
        string
        stringp
        strlen
        swap
        switch
        tail
        tell_object
        tell_room
        test_bit
        this_object
        this_player
        throw
        time
        trace
        traceprefix
        transfer
        unique_array
        upper_case
        users
        varargs
        version
        void
        while
        wizlist
        write
        write_bytes
        write_file

NOTE

        This list is accurate for the 1.5.3 driver.