Princeton's WordNet

1. approach, approaching(noun)

   the event of one object coming closer to another

   Synonyms:
   approach, attack, advance, plan of attack, glide path, feeler, coming, access, glide slope, approaching, overture, approach path, approach shot

   Antonyms:
   present(a), past

2. approach, approaching, coming(noun)

   the temporal property of becoming nearer in time

   Synonyms:
   climax, coming, feeler, approaching, advent, approach shot, glide path, glide slope, approach, approach path, orgasm, sexual climax, advance, attack, overture, access, plan of attack

   Antonyms:
   present(a), past

3. approach, approaching, coming(adj)

   the act of drawing spatially closer to something

   Synonyms:
   climax, coming, feeler, approaching, advent, approach shot, glide path, glide slope, approach, approach path, orgasm, sexual climax, advance, attack, overture, access, plan of attack

   Antonyms:
   past, present(a)

4. approaching, coming(a), forthcoming, upcoming(adj)

   of the relatively near future

   Antonyms:
   present(a), past