* Ir-: This prefix suggests a lack or absence of something, as in "irresponsible." This is the most common and straightforward choice.
* Un-: Similar to "ir-," this prefix also denotes a lack of something. You could use it to say "unaccountable" or "unreliable," both implying a lack of responsibility.
* A-: While less common, you could use "a-" to emphasize the lack of something. For example, you could say "amorphous" or "apathetic" to imply a lack of responsibility.
Other options:
* Non-: This prefix directly denotes "not," making "non-responsible" a possible option.
* Dys-: This prefix implies a malfunction or difficulty, making "dysfunctional" a potential choice, albeit a more indirect way of describing a lack of responsibility.
Ultimately, the best prefix to use depends on the specific context and the precise meaning you want to convey.