data = {'A': ['hi UK','hi IN','hi US']}
d = {'U': 'UK -- extra', 'UK': 'test Kingdom', 'IN':'India'}
d = {r'\b{}\b'.format(k):v for k, v in d.items()}
df = pd.DataFrame(data)
df['A'] = df['A'].replace(to_replace = d, regex=True)
print(df)
A
0 hi test Kingdom
1 hi India
2 hi US