eat
Ate.
now ?
sip
A three letter synonym for the exclamation 'gosh' is gee.
A three letter synonym for a verse is ode.
nee
A three letter synonym for 'present' is now.
Gob is a synonym for a seaman.
The opposite of work is play, or possibly rest.
There is no synonym for 3.
The word is "arc", although that is not the only possible meaning of that work. For example, in graph theory, an arc is a synonym for an edge of a graph.