Aperture
Active is a synonym for athletic. It starts with the letter a.
Alluvium
Boost is a synonym for the word lift and starts with the letter B.
Advance party is a synonym for in front. It starts with the letter a.
delta(Δ or δ in the Greek alphabet, also used as a mathematical symbol): alterriver delta: arm of the sea, alluvium, accumulation
alias
Angst
Imp.
Label is a synonym for handle (name).
Tour is a synonym for walk. It begins with the letter t.
postulate
boisterous