Is ethylamine a Bronsted-Lowry base?

Yes, ethylamine, $C {H}_{3} C {H}_{2} N {H}_{2}$, can act as a Bronsted-Lowry base because of the lone pair of electrons present on the nitrogen atom.
For example, when it reacts with water, ethylamine will accept a proton, ${H}^{+}$, from water and form the ethylammonium ion.
$C {H}_{3} C {H}_{2} N {H}_{2 \left(a q\right)} + {H}_{2} {O}_{\left(l\right)} r i g h t \le f t h a r p \infty n s {\overbrace{C {H}_{3} C {H}_{2} N {H}_{3 \left(a q\right)}^{+}}}^{\textcolor{b l u e}{\text{ethylammonium ion}}} + O {H}_{\left(a q\right)}^{-}$