Here's a breakdown of the phrase:
* "Every other inch" is a hyperbole, emphasizing that the person is very close to being a complete gentleman, but not quite.
* "Gentleman" refers to a person who is courteous, respectful, and possesses a sense of decorum and chivalry.
Therefore, the phrase suggests that the person in question is mostly a gentleman, but there are instances where they might slip up or behave in a way that isn't entirely consistent with the ideal of a gentleman.
For example, you might say this about someone who is generally polite and helpful, but sometimes loses their temper or says things that are a bit too blunt.
The phrase carries a slightly ironic tone, suggesting that the person's imperfections are noticeable but not necessarily detrimental to their overall character.