Oldish
/ˈəʊldɪʃ/
Definition 1 of 1
Pro Tip 1/3Relative Age
Use 'oldish' to indicate someone or something is past the middle age, but not extremely old. 
She looked oldish, perhaps in her late fifties.
Pro Tip 2/3Not Precise
'Oldish' is not exact; it shows the speaker thinks something is old without knowing the exact age. 
I'm guessing the building is oldish, likely built around the '60s.
Pro Tip 3/3Slightly Informal
The term 'oldish' is friendly and slightly informal, suitable for conversation, not for formal writing. 
My teacher is oldish but he's still full of energy.