World war II veterans. veter is a root which means for a long time
in + veter (water) + ate -> even in water (flood) a deeply rooted tree will stand still...
Inveterate = in wet(vet) ra tea tagudam...its a habitual, deeply rooted, firmly established thing to have when the climate is wet..
He had the habit of collecting information about different animals and he chose to study vet (veterinary) as his professional course.
invert + rate >>> yane jab koi shopkeeper ya koi bhaji wala rate bolata hai, tab womens ko AADAT(habitual) hoti hai bhaav karne ki
Inveterate = In + better + ate; He ated in good manner so he will lasting long.
These veteran smokers are inveterate smokers