[adj] cool and formal in manner
[adj] marked by self-restraint and reticence; "was habitually reserved in speech, withholding her opinion"-Victoria Sackville-West
[adj] set aside for the use of a particular person or party
Synonyms
aloof, bookable, booked, diffident, distant, engaged, indrawn, rarefied, rarified, restrained, reticent, set-aside(p), undemonstrative, unemotional, withdrawn