Nuestra iglesia recoge alimentos no perecederos para dar de comer a familias menesterosas.Our church collects non-perishable provisions to feed needy families.
This means that the noun can be masculine or feminine, depending on the gender of person it refers to (e.g. el doctor, la doctora).
En la entrada del supermercado siempre hay algún menesteroso pidiendo limosna.Outside the supermarket entrance, there's always some needy person begging.
menesterosos
A plural noun indicates that there is more than one person, place, thing, or idea.