Word of God is things that the authour, director, show runners, etc. have said about the story (e.g. in interviews) but don't actually show up in the text. They are not canon (or fanon, unless the fans adopt them).
Retconned Canon is things that WERE canon, but new stories have come out to say that stuff actually happened differently. They are, technically, no longer canon, but I respect people's decisions to ignore that fact. They often get recanonized if they're popular enough.
Reversely, retcons are things that happen in canon that contradict previous canon, and say that it was always this way. These are technically canon, but are at far greater risk of being written out of canon than other parts of the story, especially if they're unpopular.
Contradictions are different things that happened that invalidate each other. It doesn't make sense for all of them to have happened, but they did. Notably, ALL the contradictory events count as canon! Unlike retcons, these aren't meant to overwrite each other, they're just mistakes and bad writing.
Implications heavily overlap with interpretations, but involve what we think the creator WANTED us to believe, without ever saying. The boundary between canon and interpretation can get REALLY fuzzy here - e.g. the comics have never STATED that Tim Drake was neglected by his parents, but they've shown enough scenes that implied neglect, and side effects of neglect, that's it's reasonable to assume that we are SUPPOSED to think he was.
Or even more complex - we have Bruce Wayne doing explicitly Jewish things, like leaving stones on his parents' graves. But these are also things that racist editors might be expected to miss, which leaves the door open for him to be written as Christian, or atheist, or anything else, in the future. His Jewish status is still a heavy implication, not canon. (Notably, he's also been seen doing culturally Christian activities.)
(This is different from things like interpretations of 90s Babs and Dinah being romantically interested in each other. While those may have equal canon support, there's no sign that the authour was purposefully implying any of it. In fact, we have scripts showing he was actively trying to avoid those readings!)
