If someone of the opposite sex told you "you're looking good," is it flirting or is it just a compliment?

i told a guy before “you’re looking good” and he got all smiley and then i was hoping he didn’t take it as flirting. i really meant he looks healthy. i was complimenting him but hope he doesn’t think it’s flirting, because it wasn’t (believe me, when i flirt with people there’s no doubt).