ill-bred

ill-mannered and unrefined because of a lack of upbringing or education

It is, therefore, quite believable that many of these secret agents were as blunderful and tactless as any ill-bred son of the soil could be...

of bad breed

On the night in question, the whole house was awakened by a dreadful cats'-concert. Two or three of the gang of ill-bred, shabby cats that ran wild over the brick roofs of our town were sitting on the general's terrace screaming at the top of their repulsive voices.