If your text search for a particular keyword doesn't find a record you know that it contains that keyword here is a quick way of dumping all the text index words for a particular record (run below code in Background Scripts):
var table = "incident";
var sysID = "e8caedcbc0a80164017df472f39eaed1"; //sys_id of the record I think it contains the searched keyword
new GlideTSUtil().dumpDocument(table, sysID);
The output shows me in this case:
[0:00:00.029] Script completed in scope global: script
Tokens in incident with sysId e8caedcbc0a80164017df472f39eaed1 (docId=812)
@0 3267 inc0000003
@1 4444 0000003
@3 3270 itil
@4 3276 user
@6 4910 progress
@8 94750 aktiv
@9 94751 bearbeitung
@11 1783 high
@13 95205 hoch
@15 4679 critical
@17 95208 kritisch
@19 87 joe
@20 88 employee
@22 4827 wireless
@23 3453 access
@24 3409 down
@25 16 my
@26 1211 area
@28 3677 network
@30 28 just
@31 3898 moved
@32 18 from
@33 3284 floor
@34 3284 floor
@35 16 my
@36 4553 laptop
@37 27 cannot
@38 3467 connect
@39 3620 any
@40 4827 wireless
@41 3677 network
@43 4536 notify
@45 80800 nicht
@46 94754 benachrichtigen
@48 4236 incident
@50 4910 progress
@52 94750 aktiv
@54 1783 high
@56 95205 hoch
@58 1402 acme
@59 1394 north
@60 734 america
@62 75 beth
@63 78 anglin
@65 1783 high
@67 95205 hoch
@69 4338 normal
@71 4338 normal
@73 1003 324
@74 1225 south
@75 356 state
@76 1472 street
@77 2467 salt
@78 1589 lake
@79 1430 city
@80 2477 ut
@82 3677 network
@84 95009 netzwerk
Now, if the keyword is text indexed (part of the list above) and text search on it still doesn't work, most probably it is marked as a stop word (System Definition -> Text index Stop Words).
