Two words
May be 2 words combined (st+robus) If not obvious, probably incorrect
rob.us ADJ 1 1 NOM S M POS
robus, roba, robum ADJ [XAXEO] uncommon
red (esp. of oxen/domestic animals); red (type of wheat, other contexts);
robus N 3 2 NOM S N
robus N 3 2 VOC S N
robus N 3 2 ACC S N
robus, roboris N (3rd) N [AAXAO] Archaic
oak (tree/timber/trunk/club/post/cell); tough core; resolve/purpose; B:tetanus;
strength/firmness/solidity; vigor, robustness; potency, force, effectiveness;
military strength/might/power; heart, main strength, strongest element;
mainstay/bulwark, source of strength; stronghold, position of strength;
st INTERJ
st INTERJ [XXXDX] lesser
hush! hist!;
*

Credits:
This, our local install of the popular standby Whitaker's Words, is possible thanks to the resurrection of the venerable project at William Whitaker's Words, where you will also find extensive documentation. The corresponding GitHub repository is where you can submit issues about missing forms and analyses.
This web interface by Walter M. Shandruk.