Queer coding is when characters or relationships are given traits associated with LGBTQ people without explicitly stating that they are queer. It does not necessarily imply that the character actually is queer. But the portrayal given are likely to reference “queerness” in the audience subconscious. Queer coding can be either positive or negative.
Queerbaiting is a practice to create non-heterosexual relationships, create homoerotic moments between characters, deliberately provide non-cisgender or queer angle to a character in a narrative without actually developing it into an actual element in the story. This irrelevant detail may also be used to make fun, and channel subtle or explicit queerphobia.