1) Aloof 2) Clammed-up 3) Close-lipped 4) Cold 5) Cool and formal in manner 6) Distant 7) Hardly loquacious 8) Introverted 9) Not inclined to speak 10) Not outspoken 11) Not talkative 12) Opposite of garrulous 13) Quiet 14) Quiet rite involved money 15) Reluctant to speak 16) Reserved 17) Self-effacing 1) Aloof 2) Close mouthed 3) Enigmatic 4) Introvert 5) Reserved 6) Restrained 7) Secretive 8) Shy 9) Taciturn 10) Unassertive 11) Undemonstrative 12) Untalkative 13) Wary 
• (a.) Inclined to keep silent; reserved; uncommunicative.
Ret'i·cent adjective [ Latin reticens , present participle of reticere to keep silence; re- + tacere to be silent. See Tacit .] Inclined to keep silent; reserved; uncommunicative. 
reserved untalkative silent taciturn 
[adj] - temperamentally disinclined to talk 2. [adj] - reluctant to draw attention to yourself
reticent Reserved; disinclined to speak freely; given to silence or concealment.
self-effacing adjective reluctant to draw attention to yourself
[SAT terms] cool and formal in manner[PSAT glossary] reluctant to draw attention to yourself temperamentally disinclined to talk reluctant to draw attention to yourself[Intelligent words] temperamentally disinclined to talk