Tajrīd is a rhetorical manner of extracting, as it were, another instance of a person or quality from the person himself, thereby intensifying a description. It may involve resemblance, but its structure is not the same as straightforward simile.
لقيت من زيد أسداً
I met, from Zayd, a lion-like man.
The expression treats “a lion” as though drawn out of Zayd himself. It does not mean that a real beast emerged from him; the purpose is to magnify his courage by presenting it almost as an independent heroic figure.
Reducing tajrīd simply to “Zayd is like a lion” misses its distinctive mode of rhetorical exaggeration.