。
I didn't mean it like that.
Literal
That-kind-of intention [copula-で] [contrast-は] was-not [explanatory-んだ].
つもり ('intention, plan, mental disposition') is a key noun in Japanese for talking about what someone meant or intended to do. ~つもりではない is 'it was not (my) intention.' The んだ at the end is the explanatory ending (contraction of のだ), softening the statement and framing it as an explanation or excuse. Common phrase for clarifying after a misunderstanding.