Help with a usage of 自慢

Question

私は彼が自慢だ。

I'm Proud of Him

彼は私が自慢だ。

He is proud of me.

I am confused by this pattern with 自慢. It kind of looks like 自慢 is being used as an adjective (?), but the definition in Tangorin lists it as:

noun / noun or participle with aux. verb する → conjugation / noun with genitive case particle の

Perhaps 私は彼が自慢だ can be more literally translated as "He is my pride."?

So if I dissect it--

私は I (topic marker) 彼が he (subject/object marker) 自慢だ pride is. (?)

Along this line of reasoning, does 私は自慢だ。mean "I am proud." ?　I guess I am getting confused because I see the first sentence listed and then think of a pattern like this: 私は彼がきれいだと思います。-- "I think that he is pretty." (Where the が connects 彼 to きれい)

Would anyone be kind enough to explain this pattern with 自慢 and maybe show a few more examples like it?

For instance, these examples make more sense to me, though perhaps the English expressions do not seem to correlate as easily:

美人の妻が彼の自慢だ。 His beautiful wife is his pride.

彼女は水泳が自慢だ。 She prides herself on her swimming. (I translate it more literally as "swimming is {the source of} her pride)

Answer 1

To say "I am proud of my sister," my personal preference is

（私は）姉を誇りに思う。

instead of using 自慢. The word 自慢 can have the same connotation as "bragging," and as such I feel it deflects the attention away from what you are trying to commend. 自慢する sounds as if you are only self satisfied (something that can be a target of scorn).

For "his beautiful wife is his pride," I might rephrase as

（彼女は）彼自慢の美人妻だ。

I guess the sentence is structurally different, but it's another way of saying the same thing.

For the swimming example,

彼女は水泳（をする能力）に自信を持っている。

I feel the use of 自信をもつ implies a meaning closer to what "being proud of" conveys in this case.

All the examples in the OP do make sense, and I don't think there is anything particularly wrong, but 自慢だ is probably one of those words for which a better wording can be found, given that "being proud of" is not always synonymous in connotation as 自慢.

I suppose I didn't directly address the OP's question, to list more examples of the usage of 自慢... well I think the reason why some of the OP's examples might sound confusing is that they aren't particularly descriptive by themselves. For example

彼女は息子が自慢だ。

is a bit awkward in the same the OP's first examples are a bit confusing, but when you are more explicit like

彼女は息子が東大卒であることが自慢だ。

it sounds much better to me.