from tkinter import *
root = Tk()
root.geometry("300x250")
root.configure(bg="Gray")
root.resizable(False,False)
root.title("Palavra Invertida")
def action():
    word = variavel.get()
    reversed_word = ""
    for x in word:
        reversed_word = x + reversed_word
    lblResult['text'] = reversed_word
texto = Label(text="Digite a Palavra ",font=("Arial","15","bold"),
              bg="Gray",fg="Blue")
texto.place(relx=0.25,rely=0.2)
variavel = StringVar()
entrada = Entry(textvariable=variavel,justify='center',fg="green")
entrada.place(relx=0.05,rely=0.35,relwidth=0.9)
lblResult = Label(text = "result .......",bg="Gray")
lblResult.place(relx=0.4 ,rely=0.65)
btnAction = Button(root, text = "Validate",font=("Arial","12","bold"),
                   fg="black",bg="blue",command=action)
btnAction.place(relx=0.35,rely=0.45)
root.mainloop()

# Outra Versão

from tkinter import *
root = Tk()
root.geometry("400x400")
root.resizable(0, 0)
root.config(bg="#103030")
root.title("Inverter as palavras")

titulo = Label(text="Inverter as palavras",
               font=("Arial", "25", "bold"), bg="#103030", fg="#49e3e3")
titulo.place(relx=0.13, rely=0.05)

sub1 = Label(text="Palavra: ", font=("Arial", "18", "bold"), bg="#103030", fg="#49e3e3")
sub1.place(relx=0.1, rely=0.25)
Palavra = StringVar()
Palavra_entrada = Entry(textvariable=Palavra, font=("Arial", "12", "bold"),
                         bg="white", fg="blue", justify='center')
Palavra_entrada.place(relx=0.4, rely=0.26, relwidth=0.53)
Palavra_entrada.focus()
def limpar():
    Palavra_entrada.delete(0,END)

def app():
    word=Palavra.get()
    a=word[::-1]
    resultado_texto.config(text=a)



but1 = Button(text="Mostrar", bd=2, bg='#107db2', fg='white',
              font=('verdana', 12, 'bold'), command=app)
but1.place(relx=0.1, rely=0.45, relwidth=0.25, relheight=0.1)

but_limpar = Button(text="Limpar", bd=2, bg='#107db2', fg='white',
                    font=('verdana', 12, 'bold'), command=limpar)
but_limpar.place(relx=0.4, rely=0.45, relwidth=0.25, relheight=0.1)

but_sair = Button(text="Sair", bd=2, bg='#107db2', fg='white',
                  font=('verdana', 12, 'bold'), command=root.destroy)
but_sair.place(relx=0.7, rely=0.45, relwidth=0.25, relheight=0.1)

resultado_texto = Label(font=("Arial", 12, "bold"), bg="#cfe2f3")
resultado_texto.place(relx=0.05, rely=0.65, relwidth=0.9, relheight=0.25)
root.mainloop()