Vhdl enable without clock question
You can insert condition in each line:

library IEEE;
use IEEE.STD_LOGIC_1164.all;

entity Bin7SegDecoder is
    port( 
        enable   : in std_logic;
        binInput : in std_logic_vector(3 downto 0);
        decOut_n : out std_logic_vector(6 downto 0)
    );
end Bin7SegDecoder;

architecture Behavioral of Bin7SegDecoder is
begin
    process(binInput, enable)
    begin
        decOut_n &lt;= "1111001" when (binInput = "0001") and enable = '1' else --1
                    "0100100" when (binInput = "0010") and enable = '1' else --2
                    "0110000" when (binInput = "0011") and enable = '1' else --3
                    "0011001" when (binInput = "0100") and enable = '1' else --4
                    "0010010" when (binInput = "0101") and enable = '1' else --5
                    "0000010" when (binInput = "0110") and enable = '1' else --6
                    "1111000" when (binInput = "0111") and enable = '1' else --7
                    "0000000" when (binInput = "1000") and enable = '1' else --8
                    "0010000" when (binInput = "1001") and enable = '1' else --9
                    "0001000" when (binInput = "1010") and enable = '1' else --A
                    "0000011" when (binInput = "1011") and enable = '1' else --B
                    "1000110" when (binInput = "1100") and enable = '1' else --C
                    "0100001" when (binInput = "1101") and enable = '1' else --D
                    "0000110" when (binInput = "1110") and enable = '1' else --E
                    "0001110" when (binInput = "1111") and enable = '1' else --F
                    "1000000"; --0
    end process;

end Behavioral;


OR make one if for all statement:

...
architecture Behavioral of Bin7SegDecoder is
begin
    process(binInput, enable)
    begin
        if enable = '1' then
            decOut_n &lt;= "1111001" when (binInput = "0001") else --1
                        "0100100" when (binInput = "0010") else --2
                        "0110000" when (binInput = "0011") else --3
                        "0011001" when (binInput = "0100") else --4
                        "0010010" when (binInput = "0101") else --5
                        "0000010" when (binInput = "0110") else --6
                        "1111000" when (binInput = "0111") else --7
                        "0000000" when (binInput = "1000") else --8
                        "0010000" when (binInput = "1001") else --9
                        "0001000" when (binInput = "1010") else --A
                        "0000011" when (binInput = "1011") else --B
                        "1000110" when (binInput = "1100") else --C
                        "0100001" when (binInput = "1101") else --D
                        "0000110" when (binInput = "1110") else --E
                        "0001110" when (binInput = "1111") else --F
                        "1000000"; --0
        end if;
    end process;

end Behavioral;


But anyway you shouldn't put if outside of 
architecture Behavioral of Bin7SegDecoder is
begin
...
end Behavioral 
this part of code