1. 
[syn: retentive, recollective, long, tenacious]
2.  having the capacity to retain something; 
3.  having the power, capacity, or quality of retaining water; 
- Example: "soils retentive of moisture"
The Collaborative International Dictionary of English v.0.48:
Retentive \Re*ten"tive\, a. [Cf. F. r['e]tentif.]
   Having power to retain; as, a retentive memory.
   [1913 Webster]
         Nor airless dungeon, nor strong links of iron,
         Can be retentive to the strength of spirit. --Shak.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Retentive \Re*ten"tive\, n.
   That which retains or confines; a restraint. [R.] --Bp. Hall.
   [1913 Webster]
WordNet (r) 3.0 (2006):
retentive
    adj 1: good at remembering; "a retentive mind"; "tenacious
           memory" [syn: retentive, recollective, long,
           tenacious] [ant: forgetful, short, unretentive]
    2: having the capacity to retain something
    3: having the power, capacity, or quality of retaining water;
       "soils retentive of moisture"